Mac Developer Library Developer
Search

 

This manual page is part of Xcode Tools version 5.0

To obtain these tools:

If you are running a version of Xcode Tools other than 5.0, view the documentation locally:

  • In Xcode

  • In Terminal, using the man(1) command

Reading manual pages

Manual pages are intended as a quick reference for people who already understand a technology.

  • To learn how the manual is organized or to learn about command syntax, read the manual page for manpages(5).

  • For more information about this technology, look for other documentation in the Apple Developer Library.

  • For general information about writing shell scripts, read Shell Scripting Primer.



curl_easy_setopt(3)                            libcurl Manual                            curl_easy_setopt(3)



NAME
       curl_easy_setopt - set options for a curl easy handle

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLoption option, parameter);

DESCRIPTION
       curl_easy_setopt()  is  used  to  tell  libcurl  how  to  behave. By using the appropriate options to
       curl_easy_setopt, you can change libcurl's behavior.  All options are set with the option followed by
       a  parameter.  That  parameter  can be a long, a function pointer, an object pointer or a curl_off_t,
       depending on what the specific option expects. Read this manual carefully as  bad  input  values  may
       cause libcurl to behave badly!  You can only set one option in each function call. A typical applica-tion application
       tion uses many curl_easy_setopt() calls in the setup phase.

       Options set with this function call are valid for all forthcoming transfers performed using this han-dle. handle.
       dle.   The  options  are  not in any way reset between transfers, so if you want subsequent transfers
       with different options, you must change them between the transfers.  You  can  optionally  reset  all
       options back to internal default with curl_easy_reset(3).

       Strings  passed  to libcurl as 'char *' arguments, are copied by the library; thus the string storage
       associated to the pointer argument may be overwritten after curl_easy_setopt() returns. Exceptions to
       this rule are described in the option details below.

       Before version 7.17.0, strings were not copied. Instead the user was forced keep them available until
       libcurl no longer needed them.

       The handle is the return code from a curl_easy_init(3) or curl_easy_duphandle(3) call.

BEHAVIOR OPTIONS
       CURLOPT_VERBOSE
              Set the parameter to 1 to get the library to display a lot of verbose  information  about  its
              operations.  Very  useful for libcurl and/or protocol debugging and understanding. The verbose
              information will be sent to stderr, or the stream set with CURLOPT_STDERR. The  default  value
              for this parameter is 0.

              You  hardly  ever  want  this set in production use, you will almost always want this when you
              debug/report problems. Another neat option for debugging is the CURLOPT_DEBUGFUNCTION.

       CURLOPT_HEADER
              A parameter set to 1 tells the library to include the header in the body output. This is  only
              relevant  for protocols that actually have headers preceding the data (like HTTP). The default
              value for this parameter is 0.

       CURLOPT_NOPROGRESS
              Pass a long. If set to 1, it tells the library to shut off the progress meter  completely.  It
              will also prevent the CURLOPT_PROGRESSFUNCTION from getting called. The default value for this
              parameter is 1.

              Future versions of libcurl are likely to not have any built-in progress meter at all.

       CURLOPT_NOSIGNAL
              Pass a long. If it is 1, libcurl will not use any functions that install  signal  handlers  or
              any  functions  that  cause  signals  to be sent to the process. This option is mainly here to
              allow multi-threaded unix applications to still set/use all timeout options etc, without risk-ing risking
              ing getting signals.  The default value for this parameter is 0.  (Added in 7.10)

              If  this  option  is  set and libcurl has been built with the standard name resolver, timeouts
              will not occur while the name resolve takes place.  Consider building libcurl with c-ares sup-port support
              port to enable asynchronous DNS lookups, which enables nice timeouts for name resolves without
              signals.

              Setting CURLOPT_NOSIGNAL to 1 makes libcurl NOT ask the  system  to  ignore  SIGPIPE  signals,
              which otherwise are sent by the system when trying to send data to a socket which is closed in
              the other end. libcurl makes an effort to never cause such SIGPIPEs to trigger, but some oper-ating operating
              ating  systems  have  no  way  to avoid them and even on those that have there are some corner
              cases when they may still happen, contrary to our desire. In addition, using  CURLAUTH_NTLM_WB
              authentication could cause a SIGCHLD signal to be raised.

       CURLOPT_WILDCARDMATCH
              Set  this option to 1 if you want to transfer multiple files according to a file name pattern.
              The pattern can be specified as part of the CURLOPT_URL option, using an fnmatch-like  pattern
              (Shell Pattern Matching) in the last part of URL (file name).

              By  default,  libcurl uses its internal wildcard matching implementation. You can provide your
              own matching function by the CURLOPT_FNMATCH_FUNCTION option.

              This feature is only supported by the FTP download for now.

              A brief introduction of its syntax follows:

              * - ASTERISK
                     ftp://example.com/some/path/*.txt (for all txt's from the root directory)

              ? - QUESTION MARK
                     Question mark matches any (exactly one) character.

                     ftp://example.com/some/path/photo?.jpeg

              [ - BRACKET EXPRESSION
                     The left bracket opens a bracket expression. The question mark  and  asterisk  have  no
                     special  meaning  in  a  bracket  expression. Each bracket expression ends by the right
                     bracket and matches exactly one character. Some examples follow:

                     [a-zA-Z0-9] or [f-gF-G] - character interval

                     [abc] - character enumeration

                     [^abc] or [!abc] - negation

                     [[:name:]] class expression. Supported classes are alnum,lower,  space,  alpha,  digit,
                     print, upper, blank, graph, xdigit.

                     [][-!^]  - special case - matches only '-', ']', '[', '!' or '^'. These characters have
                     no special purpose.

                     [\[\]\\] - escape syntax. Matches '[', ']' or '\'.

                     Using the rules above, a file name pattern can be constructed:

                     ftp://example.com/some/path/[a-z[:upper:]\\].jpeg

       (This was added in 7.21.0)

CALLBACK OPTIONS
       CURLOPT_WRITEFUNCTION
              Pass a pointer to a function that matches the following prototype: size_t function( char *ptr,
              size_t  size,  size_t  nmemb, void *userdata); This function gets called by libcurl as soon as
              there is data received that needs to be saved. The size of the data pointed to by ptr is  size
              multiplied  with  nmemb,  it  will not be zero terminated. Return the number of bytes actually
              taken care of. If that amount differs from the amount passed to your function, it'll signal an
              error to the library. This will abort the transfer and return CURLE_WRITE_ERROR.

              From  7.18.0,  the  function  can return CURL_WRITEFUNC_PAUSE which then will cause writing to
              this connection to become paused. See curl_easy_pause(3) for further details.

              This function may be called with zero bytes data if the transferred file is empty.

              Set this option to NULL to get the internal default function. The  internal  default  function
              will write the data to the FILE * given with CURLOPT_WRITEDATA.

              Set the userdata argument with the CURLOPT_WRITEDATA option.

              The  callback  function will be passed as much data as possible in all invokes, but you cannot
              possibly make any assumptions. It may be one byte, it may be thousands. The maximum amount  of
              body  data  that  can  be  passed  to the write callback is defined in the curl.h header file:
              CURL_MAX_WRITE_SIZE (the usual default is 16K). If you however have CURLOPT_HEADER set,  which
              sends  header  data  to  the  write  callback, you can get up to CURL_MAX_HTTP_HEADER bytes of
              header data passed into it. This usually means 100K.

       CURLOPT_WRITEDATA
              Data pointer to pass to the file write function. If you use the CURLOPT_WRITEFUNCTION  option,
              this is the pointer you'll get as input. If you don't use a callback, you must pass a 'FILE *'
              (cast to 'void *') as libcurl will pass this to fwrite() when writing data.  By  default,  the
              value of this parameter is unspecified.

              The  internal  CURLOPT_WRITEFUNCTION will write the data to the FILE * given with this option,
              or to stdout if this option hasn't been set.

              If you're using libcurl as a win32 DLL, you MUST use the CURLOPT_WRITEFUNCTION if you set this
              option or you will experience crashes.

              This  option  is  also  known with the older name CURLOPT_FILE, the name CURLOPT_WRITEDATA was
              introduced in 7.9.7.

       CURLOPT_READFUNCTION
              Pass a pointer to a function that matches the following prototype: size_t function( void *ptr,
              size_t size, size_t nmemb, void *userdata); This function gets called by libcurl as soon as it
              needs to read data in order to send it to the peer. The data area pointed at  by  the  pointer
              ptr  may be filled with at most size multiplied with nmemb number of bytes. Your function must
              return the actual number of bytes that you stored in that memory area. Returning 0 will signal
              end-of-file to the library and cause it to stop the current transfer.

              If you stop the current transfer by returning 0 "pre-maturely" (i.e before the server expected
              it, like when you've said you will upload N bytes and you upload less than N bytes),  you  may
              experience that the server "hangs" waiting for the rest of the data that won't come.

              The  read  callback  may return CURL_READFUNC_ABORT to stop the current operation immediately,
              resulting in a CURLE_ABORTED_BY_CALLBACK error code from the transfer (Added in 7.12.1)

              From 7.18.0, the function can return CURL_READFUNC_PAUSE which then will  cause  reading  from
              this connection to become paused. See curl_easy_pause(3) for further details.

              Bugs:  when  doing  TFTP  uploads,  you must return the exact amount of data that the callback
              wants, or it will be considered the final packet by the server end and the transfer  will  end
              there.

              If  you  set  this callback pointer to NULL, or don't set it at all, the default internal read
              function will be used. It is doing an fread() on the FILE * userdata  set  with  CURLOPT_READ-DATA. CURLOPT_READDATA.
              DATA.

       CURLOPT_READDATA
              Data  pointer  to  pass to the file read function. If you use the CURLOPT_READFUNCTION option,
              this is the pointer you'll get as input. If you don't specify a read callback but instead rely
              on  the  default  internal  read  function, this data must be a valid readable FILE * (cast to
              'void *').

              If you're using libcurl as a win32 DLL, you MUST use a CURLOPT_READFUNCTION if  you  set  this
              option.

              This  option  was  also  known by the older name CURLOPT_INFILE, the name CURLOPT_READDATA was
              introduced in 7.9.7.

       CURLOPT_IOCTLFUNCTION
              Pass a pointer to a function that matches the  following  prototype:  curlioerr  function(CURL
              *handle, int cmd, void *clientp);. This function gets called by libcurl when something special
              I/O-related needs to be done that the library can't do by itself. For now, rewinding the  read
              data  stream  is  the only action it can request. The rewinding of the read data stream may be
              necessary when doing a HTTP PUT or POST with a multi-pass authentication method.  By  default,
              this parameter is set to NULL.  (Option added in 7.12.3).

              Use  CURLOPT_SEEKFUNCTION  instead  to  provide  seeking! If CURLOPT_SEEKFUNCTION is set, this
              parameter will be ignored when seeking.

       CURLOPT_IOCTLDATA
              Pass a pointer that will be untouched by libcurl and passed as the 3rd argument in  the  ioctl
              callback  set with CURLOPT_IOCTLFUNCTION.  By default, the value of this parameter is unspeci-fied. unspecified.
              fied.  (Option added in 7.12.3)

       CURLOPT_SEEKFUNCTION
              Pass a pointer  to  a  function  that  matches  the  following  prototype:  int  function(void
              *instream,  curl_off_t  offset, int origin); This function gets called by libcurl to seek to a
              certain position in the input stream and can be used to fast  forward  a  file  in  a  resumed
              upload  (instead  of reading all uploaded bytes with the normal read function/callback). It is
              also called to rewind a stream when doing a HTTP PUT or POST with a multi-pass  authentication
              method.  The  function  shall work like "fseek" or "lseek" and accepted SEEK_SET, SEEK_CUR and
              SEEK_END as argument for origin, although (in 7.18.0) libcurl only passes SEEK_SET. The  call-back callback
              back  must  return 0 (CURL_SEEKFUNC_OK) on success, 1 (CURL_SEEKFUNC_FAIL) to cause the upload
              operation to fail or 2 (CURL_SEEKFUNC_CANTSEEK)  to  indicate  that  while  the  seek  failed,
              libcurl  is  free  to work around the problem if possible. The latter can sometimes be done by
              instead reading from the input or similar.

              By default, this parameter is unset.

              If you forward the input arguments directly to "fseek" or "lseek", note that the data type for
              offset is not the same as defined for curl_off_t on many systems! (Option added in 7.18.0)

       CURLOPT_SEEKDATA
              Data  pointer  to  pass to the file seek function. If you use the CURLOPT_SEEKFUNCTION option,
              this is the pointer you'll get as input. If you don't specify a seek callback, NULL is passed.
              (Option added in 7.18.0)

       CURLOPT_SOCKOPTFUNCTION
              Pass a pointer to a function that matches the following prototype: int function(void *clientp,
              curl_socket_t curlfd, curlsocktype purpose);. By default, this parameter  is  unset.  If  set,
              this  function  gets  called by libcurl after the socket() call but before the connect() call.
              The callback's purpose argument identifies the exact purpose for this particular socket:

              CURLSOCKTYPE_IPCXN for actively created connections or since  7.28.0  CURLSOCKTYPE_ACCEPT  for
              FTP  when  the  connection was setup with PORT/EPSV (in earlier versions these sockets weren't
              passed to this callback).

              Future versions of libcurl may support more purposes.  It  passes  the  newly  created  socket
              descriptor  so  additional  setsockopt() calls can be done at the user's discretion.  Return 0
              (zero) from the callback on success. Return 1 from the callback function to signal an unrecov-erable unrecoverable
              erable  error  to  the  library and it will close the socket and return CURLE_COULDNT_CONNECT.
              (Option added in 7.16.0)

              Added in 7.21.5, the callback function may return CURL_SOCKOPT_ALREADY_CONNECTED, which  tells
              libcurl that the socket is in fact already connected and then libcurl will not attempt to con-nect connect
              nect it.

       CURLOPT_SOCKOPTDATA
              Pass a pointer that will be untouched by libcurl and passed as the first argument in the sock-opt sockopt
              opt callback set with CURLOPT_SOCKOPTFUNCTION.  The default value of this parameter is unspec-ified. unspecified.
              ified.  (Option added in 7.16.0)

       CURLOPT_OPENSOCKETFUNCTION
              Pass a pointer to a function that matches the following prototype: curl_socket_t function(void
              *clientp,  curlsocktype purpose, struct curl_sockaddr *address);. This function gets called by
              libcurl instead of the socket(2) call. The callback's purpose argument  identifies  the  exact
              purpose  for  this  particular  socket: CURLSOCKTYPE_IPCXN is for IP based connections. Future
              versions of libcurl may support more purposes. It  passes  the  resolved  peer  address  as  a
              address argument so the callback can modify the address or refuse to connect at all. The call-back callback
              back function should return the socket or CURL_SOCKET_BAD  in  case  no  connection  could  be
              established  or  another error was detected. Any additional setsockopt(2) calls can be done on
              the socket at the user's discretion.  CURL_SOCKET_BAD return value from the callback  function
              will  signal  an  unrecoverable error to the library and it will return CURLE_COULDNT_CONNECT.
              This return code can be used for IP address blacklisting.  The default behavior is:
                 return socket(addr->family, addr->socktype, addr->protocol);
              (Option added in 7.17.1.)

       CURLOPT_OPENSOCKETDATA
              Pass a pointer that will be untouched by libcurl and passed  as  the  first  argument  in  the
              opensocket  callback set with CURLOPT_OPENSOCKETFUNCTION.  The default value of this parameter
              is unspecified.  (Option added in 7.17.1.)

       CURLOPT_CLOSESOCKETFUNCTION
              Pass a pointer to a function that matches the following prototype: int function(void *clientp,
              curl_socket_t  item);.  This  function gets called by libcurl instead of the close(3) or clos-esocket(3) closesocket(3)
              esocket(3) call when sockets are closed (not for any other file descriptors). This  is  pretty
              much the reverse to the CURLOPT_OPENSOCKETFUNCTION option. Return 0 to signal success and 1 if
              there was an error.  (Option added in 7.21.7)

       CURLOPT_CLOSESOCKETDATA
              Pass a pointer that will be untouched by libcurl and passed as the first argument in the clos-esocket closesocket
              esocket callback set with CURLOPT_CLOSESOCKETFUNCTION.  The default value of this parameter is
              unspecified.  (Option added in 7.21.7)

       CURLOPT_PROGRESSFUNCTION
              Pass a pointer to a function that matches the following prototype: int function(void *clientp,
              double  dltotal,  double  dlnow, double ultotal, double ulnow); . This function gets called by
              libcurl instead of its internal equivalent with a frequent interval during operation  (roughly
              once  per  second  or  sooner)  no matter if data is being transferred or not.  Unknown/unused
              argument values passed to the callback will be set to zero (like if you  only  download  data,
              the  upload  size  will  remain  0).  Returning a non-zero value from this callback will cause
              libcurl to abort the transfer and return CURLE_ABORTED_BY_CALLBACK.

              If you transfer data with the multi interface, this function will not be called during periods
              of idleness unless you call the appropriate libcurl function that performs transfers.

              CURLOPT_NOPROGRESS must be set to 0 to make this function actually get called.

       CURLOPT_PROGRESSDATA
              Pass  a  pointer  that  will  be  untouched by libcurl and passed as the first argument in the
              progress callback set with CURLOPT_PROGRESSFUNCTION.  The default value of this  parameter  is
              unspecified.

       CURLOPT_HEADERFUNCTION
              Pass a pointer to a function that matches the following prototype: size_t function( void *ptr,
              size_t size, size_t nmemb, void *userdata);. This function gets called by libcurl as  soon  as
              it  has received header data. The header callback will be called once for each header and only
              complete header lines are passed on to the callback. Parsing headers is very easy using  this.
              The  size  of the data pointed to by ptr is size multiplied with nmemb. Do not assume that the
              header line is zero terminated! The pointer named userdata is the one you set  with  the  CUR-LOPT_WRITEHEADER CURLOPT_WRITEHEADER
              LOPT_WRITEHEADER  option. The callback function must return the number of bytes actually taken
              care of. If that amount differs from the amount passed to your function, it'll signal an error
              to the library. This will abort the transfer and return CURL_WRITE_ERROR.

              A  complete  HTTP  header  that  is  passed to this function can be up to CURL_MAX_HTTP_HEADER
              (100K) bytes.

              If this option is not set, or if it is set to  NULL,  but  CURLOPT_HEADERDATA  (CURLOPT_WRITE-HEADER) (CURLOPT_WRITEHEADER)
              HEADER)  is  set  to anything but NULL, the function used to accept response data will be used
              instead. That is, it will be the function specified with CURLOPT_WRITEFUNCTION, or  if  it  is
              not specified or NULL - the default, stream-writing function.

              It's  important  to  note  that  the callback will be invoked for the headers of all responses
              received after initiating a request and  not  just  the  final  response.  This  includes  all
              responses  which  occur  during authentication negotiation. If you need to operate on only the
              headers from the final response, you will need to collect headers in the callback yourself and
              use HTTP status lines, for example, to delimit response boundaries.

              When  a  server  sends  a  chunked encoded transfer, it may contain a trailer. That trailer is
              identical to a HTTP header and if such a trailer is received it is passed to  the  application
              using  this  callback  as well. There are several ways to detect it being a trailer and not an
              ordinary header: 1) it comes after the response-body. 2) it comes after the final header  line
              (CR  LF)  3)  a  Trailer:  header among the regular response-headers mention what header(s) to
              expect in the trailer.

              For non-HTTP protocols like FTP, POP3, IMAP and SMTP this function will get  called  with  the
              server responses to the commands that libcurl sends.

       CURLOPT_WRITEHEADER
              (This  option  is  also  known  as  CURLOPT_HEADERDATA) Pass a pointer to be used to write the
              header part of the received data to. If you don't use CURLOPT_WRITEFUNCTION or CURLOPT_HEADER-FUNCTION CURLOPT_HEADERFUNCTION
              FUNCTION to take care of the writing, this must be a valid FILE * as the internal default will
              then be a plain fwrite(). See also the CURLOPT_HEADERFUNCTION option above on  how  to  set  a
              custom get-all-headers callback.

       CURLOPT_DEBUGFUNCTION
              Pass  a  pointer  to  a function that matches the following prototype: int curl_debug_callback
              (CURL *, curl_infotype, char *, size_t, void *); CURLOPT_DEBUGFUNCTION replaces  the  standard
              debug  function used when CURLOPT_VERBOSE  is in effect. This callback receives debug informa-tion, information,
              tion, as specified with the curl_infotype argument. This function must  return  0.   The  data
              pointed  to  by  the  char  * passed to this function WILL NOT be zero terminated, but will be
              exactly of the size as told by the size_t argument.

              Available curl_infotype values:

              CURLINFO_TEXT
                     The data is informational text.

              CURLINFO_HEADER_IN
                     The data is header (or header-like) data received from the peer.

              CURLINFO_HEADER_OUT
                     The data is header (or header-like) data sent to the peer.

              CURLINFO_DATA_IN
                     The data is protocol data received from the peer.

              CURLINFO_DATA_OUT
                     The data is protocol data sent to the peer.

       CURLOPT_DEBUGDATA
              Pass a pointer to whatever you want passed in to your CURLOPT_DEBUGFUNCTION in the last void *
              argument. This pointer is not used by libcurl, it is only passed to the callback.

       CURLOPT_SSL_CTX_FUNCTION
              This  option  does  only function for libcurl powered by OpenSSL. If libcurl was built against
              another SSL library, this functionality is absent.

              Pass a pointer to a function that matches the  following  prototype:  CURLcode  sslctxfun(CURL
              *curl,  void  *sslctx,  void *parm); This function gets called by libcurl just before the ini-tialization initialization
              tialization of a SSL connection after having processed all other SSL related options to give a
              last  chance  to  an  application to modify the behaviour of openssl's ssl initialization. The
              sslctx parameter is actually a pointer to an openssl SSL_CTX.  If  an  error  is  returned  no
              attempt to establish a connection is made and the perform operation will return the error code
              from this callback function.  Set the parm argument with the CURLOPT_SSL_CTX_DATA option. This
              option was introduced in 7.11.0.

              This function will get called on all new connections made to a server, during the SSL negotia-tion. negotiation.
              tion. The SSL_CTX pointer will be a new one every time.

              To use this properly, a non-trivial amount of knowledge of the openssl libraries is necessary.
              For example, using this function allows you to use openssl callbacks to add additional valida-tion validation
              tion code for certificates, and even to change the actual URI of a HTTPS request (example used
              in the lib509 test case).  See also the example section for a replacement of the key, certifi-cate certificate
              cate and trust file settings.

       CURLOPT_SSL_CTX_DATA
              Data pointer to pass to the ssl context callback set by the  option  CURLOPT_SSL_CTX_FUNCTION,
              this is the pointer you'll get as third parameter, otherwise NULL. (Added in 7.11.0)

       CURLOPT_CONV_TO_NETWORK_FUNCTION

       CURLOPT_CONV_FROM_NETWORK_FUNCTION

       CURLOPT_CONV_FROM_UTF8_FUNCTION
              Pass  a  pointer  to  a  function that matches the following prototype: CURLcode function(char
              *ptr, size_t length);

              These  three  options  apply  to  non-ASCII  platforms  only.   They  are  available  only  if
              CURL_DOES_CONVERSIONS  was  defined  when  libcurl was built. When this is the case, curl_ver-sion_info(3) curl_version_info(3)
              sion_info(3) will return the CURL_VERSION_CONV feature bit set.

              The data to be converted is in a buffer pointed to by the ptr parameter.  The amount  of  data
              to  convert  is indicated by the length parameter.  The converted data overlays the input data
              in the buffer pointed to by the ptr parameter.  CURLE_OK should be  returned  upon  successful
              conversion.   A  CURLcode return value defined by curl.h, such as CURLE_CONV_FAILED, should be
              returned if an error was encountered.

              CURLOPT_CONV_TO_NETWORK_FUNCTION and CURLOPT_CONV_FROM_NETWORK_FUNCTION  convert  between  the
              host  encoding  and  the  network  encoding.   They  are  used when commands or ASCII data are
              sent/received over the network.

              CURLOPT_CONV_FROM_UTF8_FUNCTION is called to convert from UTF8 into the host encoding.  It  is
              required only for SSL processing.

              If  you  set  a  callback  pointer to NULL, or don't set it at all, the built-in libcurl iconv
              functions will be used.  If HAVE_ICONV was not defined when libcurl was built, and no callback
              has been established, conversion will return the CURLE_CONV_REQD error code.

              If HAVE_ICONV is defined, CURL_ICONV_CODESET_OF_HOST must also be defined.  For example:

               #define CURL_ICONV_CODESET_OF_HOST "IBM-1047"

              The iconv code in libcurl will default the network and UTF8 codeset names as follows:

               #define CURL_ICONV_CODESET_OF_NETWORK "ISO8859-1"

               #define CURL_ICONV_CODESET_FOR_UTF8   "UTF-8"

              You will need to override these definitions if they are different on your system.

       CURLOPT_INTERLEAVEFUNCTION
              Pass a pointer to a function that matches the following prototype: size_t function( void *ptr,
              size_t size, size_t nmemb, void *userdata). This function gets called by libcurl as soon as it
              has  received  interleaved  RTP data. This function gets called for each $ block and therefore
              contains exactly one upper-layer protocol unit (e.g.  one RTP packet). Curl writes the  inter-leaved interleaved
              leaved  header  as  well as the included data for each call. The first byte is always an ASCII
              dollar sign. The dollar sign is followed by a one byte channel identifier and then  a  2  byte
              integer  length  in  network byte order. See RFC2326 Section 1_.12 for more information on how
              RTP interleaving behaves. If unset or set to NULL, curl will use the default write function.

              Interleaved RTP poses some challenges for the client application. Since  the  stream  data  is
              sharing the RTSP control connection, it is critical to service the RTP in a timely fashion. If
              the RTP data is not handled quickly, subsequent response processing  may  become  unreasonably
              delayed  and the connection may close. The application may use CURL_RTSPREQ_RECEIVE to service
              RTP  data  when  no  requests  are  desired.  If  the  application  makes  a  request,   (e.g.
              CURL_RTSPREQ_PAUSE) then the response handler will process any pending RTP data before marking
              the request as finished.  (Added in 7.20.0)

       CURLOPT_INTERLEAVEDATA
              This is the userdata pointer that will be passed  to  CURLOPT_INTERLEAVEFUNCTION  when  inter-leaved interleaved
              leaved RTP data is received. (Added in 7.20.0)

       CURLOPT_CHUNK_BGN_FUNCTION
              Pass  a  pointer to a function that matches the following prototype: long function (const void
              *transfer_info, void *ptr, int remains). This function gets called by libcurl before a part of
              the stream is going to be transferred (if the transfer supports chunks).

              This callback makes sense only when using the CURLOPT_WILDCARDMATCH option for now.

              The  target of transfer_info parameter is a "feature depended" structure. For the FTP wildcard
              download, the target is curl_fileinfo structure (see curl/curl.h).  The  parameter  ptr  is  a
              pointer given by CURLOPT_CHUNK_DATA. The parameter remains contains number of chunks remaining
              per the transfer. If the feature is not available, the parameter has zero value.

              Return CURL_CHUNK_BGN_FUNC_OK if everything is fine, CURL_CHUNK_BGN_FUNC_SKIP if you  want  to
              skip  the  concrete  chunk  or  CURL_CHUNK_BGN_FUNC_FAIL to tell libcurl to stop if some error
              occurred.  (This was added in 7.21.0)

       CURLOPT_CHUNK_END_FUNCTION
              Pass a pointer to a function that matches the following prototype: long  function(void  *ptr).
              This  function gets called by libcurl as soon as a part of the stream has been transferred (or
              skipped).

              Return CURL_CHUNK_END_FUNC_OK if everything is fine or CURL_CHUNK_END_FUNC_FAIL  to  tell  the
              lib to stop if some error occurred.  (This was added in 7.21.0)

       CURLOPT_CHUNK_DATA
              Pass  a  pointer  that  will  be  untouched  by  libcurl and passed as the ptr argument to the
              CURL_CHUNK_BGN_FUNTION and CURL_CHUNK_END_FUNTION.  (This was added in 7.21.0)

       CURLOPT_FNMATCH_FUNCTION
              Pass a pointer to a function that matches the following  prototype:  int  function(void  *ptr,
              const  char  *pattern,  const char *string) prototype (see curl/curl.h). It is used internally
              for the wildcard matching feature.

              Return CURL_FNMATCHFUNC_MATCH if pattern matches the string, CURL_FNMATCHFUNC_NOMATCH  if  not
              or CURL_FNMATCHFUNC_FAIL if an error occurred.  (This was added in 7.21.0)

       CURLOPT_FNMATCH_DATA
              Pass  a  pointer  that  will  be  untouched  by  libcurl and passed as the ptr argument to the
              CURL_FNMATCH_FUNCTION. (This was added in 7.21.0)

ERROR OPTIONS
       CURLOPT_ERRORBUFFER
              Pass a char * to a buffer that the libcurl may store human readable error  messages  in.  This
              may  be  more  helpful than just the return code from curl_easy_perform. The buffer must be at
              least CURL_ERROR_SIZE big.  Although this argument is a 'char *',  it  does  not  describe  an
              input  string.  Therefore the (probably undefined) contents of the buffer is NOT copied by the
              library. You must keep the associated storage available until  libcurl  no  longer  needs  it.
              Failing  to do so will cause very odd behavior or even crashes. libcurl will need it until you
              call curl_easy_cleanup(3) or you set the same option again to use a different pointer.

              Use CURLOPT_VERBOSE and CURLOPT_DEBUGFUNCTION to better debug/trace why errors happen.

              If the library does not return an error, the buffer may not have been touched. Do not rely  on
              the contents in those cases.


       CURLOPT_STDERR
              Pass a FILE * as parameter. Tell libcurl to use this stream instead of stderr when showing the
              progress meter and displaying CURLOPT_VERBOSE data.

       CURLOPT_FAILONERROR
              A parameter set to 1 tells the library to fail silently if the HTTP code returned is equal  to
              or  larger  than  400.  The default action would be to return the page normally, ignoring that
              code.

              This method is not fail-safe and there are occasions where non-successful response codes  will
              slip through, especially when authentication is involved (response codes 401 and 407).

              You might get some amounts of headers transferred before this situation is detected, like when
              a "100-continue" is received as a response to a POST/PUT and a 401 or 407 is received  immedi-ately immediately
              ately afterwards.

NETWORK OPTIONS
       CURLOPT_URL
              Pass  in  a pointer to the actual URL to deal with. The parameter should be a char * to a zero
              terminated string which must be URL-encoded in the following format:

              scheme://host:port/path

              For a greater explanation of the format please see RFC3986.

              If the given URL lacks the scheme, or protocol, part ("http://" or "ftp://" etc), libcurl will
              attempt  to resolve which protocol to use based on the given host mame. If the protocol is not
              supported, libcurl will return (CURLE_UNSUPPORTED_PROTOCOL) when you call curl_easy_perform(3)
              or curl_multi_perform(3). Use curl_version_info(3) for detailed information on which protocols
              are supported.

              The host part of the URL contains the address of the server that you want to connect to.  This
              can be the fully qualified domain name of the server, the local network name of the machine on
              your network or the IP address of the server or machine represented by either an IPv4 or  IPv6
              address. For example:

              http://www.example.com/

              http://hostname/

              http://192.168.0.1/

              http://[2001:1890:1112:1::20]/

              It is also possible to specify the user name and password as part of the host, for some proto-cols, protocols,
              cols, when connecting to servers that require authentication.

              For example the following types of authentication support this:

              http://user:password@www.example.com

              ftp://user:password@ftp.example.com

              pop3://user:password@mail.example.com

              The port is optional and when not specified libcurl will use the default  port  based  on  the
              determined  or specified protocol: 80 for HTTP, 21 for FTP and 25 for SMTP, etc. The following
              examples show how to specify the port:

              http://www.example.com:8080/ - This will connect to a web server using port 8080  rather  than
              80.

              smtp://mail.example.com:587/  -  This  will  connect  to a SMTP server on the alternative mail
              port.

              The path part of the URL is protocol specific and whilst some examples are  given  below  this
              list is not conclusive:

              HTTP

              The path part of a HTTP request specifies the file to retrieve and from what directory. If the
              directory is not specified then the web server's root directory is used. If the file is  omit-ted omitted
              ted then the default document will be retrieved for either the directory specified or the root
              directory. The exact resource returned for each URL is entirely dependent on the server's con-figuration. configuration.
              figuration.

              http://www.example.com - This gets the main page from the web server.

              http://www.example.com/index.html - This returns the main page by explicitly requesting it.

              http://www.example.com/contactus/  -  This  returns  the  default  document from the contactus
              directory.

              FTP

              The path part of an FTP request specifies the file to retrieve and from what directory. If the
              file part is omitted then libcurl downloads the directory listing for the directory specified.
              If the directory is omitted then the directory listing for the root / home directory  will  be
              returned.

              ftp://ftp.example.com - This retrieves the directory listing for the root directory.

              ftp://ftp.example.com/readme.txt - This downloads the file readme.txt from the root directory.

              ftp://ftp.example.com/libcurl/readme.txt - This downloads readme.txt from the  libcurl  direc-tory. directory.
              tory.

              ftp://user:password@ftp.example.com/readme.txt  -  This retrieves the readme.txt file from the
              user's home directory. When a username and password is specified, everything that is specified
              in  the  path  part  is relative to the user's home directory. To retrieve files from the root
              directory or a directory underneath the root directory then the absolute path must  be  speci-fied specified
              fied by prepending an additional forward slash to the beginning of the path.

              ftp://user:password@ftp.example.com//readme.txt  - This retrieves the readme.txt from the root
              directory when logging in as a specified user.

              SMTP

              The path part of a SMTP request specifies the host name to present during  communication  with
              the  mail  server.  If the path is omitted then libcurl will attempt to resolve the local com-puter's computer's
              puter's host name. However, this may not return  the  fully  qualified  domain  name  that  is
              required  by some mail servers and specifying this path allows you to set an alternative name,
              such as your machine's fully qualified domain name, which you  might  have  obtained  from  an
              external function such as gethostname or getaddrinfo.

              smtp://mail.example.com - This connects to the mail server at example.com and sends your local
              computer's host name in the HELO / EHLO command.

              smtp://mail.example.com/client.example.com - This will send client.example.com in the  HELO  /
              EHLO command to the mail server at example.com.

              POP3

              The  path part of a POP3 request specifies the message ID to retrieve. If the ID is not speci-fied specified
              fied then a list of waiting messages is returned instead.

              pop3://user:password@mail.example.com - This lists the available messages for the user

              pop3://user:password@mail.example.com/1 - This retrieves the first message for the user

              IMAP

              The path part of an IMAP request not only specifies the mailbox to list (Added in  7.30.0)  or
              select,  but  can  also be used to check the UIDVALIDITY of the mailbox and to specify the UID
              and SECTION of the message to fetch (Added in 7.30.0).

              imap://user:password@mail.example.com - Performs a top level folder list

              imap://user:password@mail.example.com/INBOX - Performs a folder list on the user's inbox

              imap://user:password@mail.example.com/INBOX/;UID=1 - Selects the user's inbox and fetches mes-sage message
              sage 1

              imap://user:password@mail.example.com/INBOX;UIDVALIDITY=50/;UID=2  - Selects the user's inbox,
              checks the UIDVALIDITY of the mailbox is 50 and fetches message 2 if it is

              imap://user:password@mail.example.com/INBOX/;UID=3/;SECTION=TEXT - Selects  the  user's  inbox
              and fetches message 3 with only the text portion of the message

              For more information about the individual components of an IMAP URL please see RFC5092.

              SCP

              The  path  part  of  a SCP request specifies the file to retrieve and from what directory. The
              file part may not be omitted. The file is taken as an absolute path from the root directory on
              the  server. To specify a path relative to the user's home directory on the server, prepend ~/
              to the path portion.  If the user name is not embedded in the URL, it can be set with the CUR-LOPT_USERPWD CURLOPT_USERPWD
              LOPT_USERPWD or CURLOPT_USERNAME option.

              scp://user@example.com/etc/issue - This specifies the file /etc/issue

              scp://example.com/~/my-file  - This specifies the file my-file in the user's home directory on
              the server

              SFTP

              The path part of a SFTP request specifies the file to retrieve and from what directory. If the
              file part is omitted then libcurl downloads the directory listing for the directory specified.
              If the path ends in a / then a directory listing is returned instead of a file.  If  the  path
              is omitted entirely then the directory listing for the root / home directory will be returned.
              If the user name is not embedded in the URL, it can be set with the  CURLOPT_USERPWD  or  CUR-LOPT_USERNAME CURLOPT_USERNAME
              LOPT_USERNAME option.

              sftp://user:password@example.com/etc/issue - This specifies the file /etc/issue

              sftp://user@example.com/~/my-file  - This specifies the file my-file in the user's home direc-tory directory
              tory

              sftp://ssh.example.com/~/Documents/ - This requests  a  directory  listing  of  the  Documents
              directory under the user's home directory

              LDAP

              The  path  part  of a LDAP request can be used to specify the: Distinguished Name, Attributes,
              Scope, Filter and Extension for a LDAP search. Each field is separated by a question mark  and
              when  that  field  is  not required an empty string with the question mark separator should be
              included.

              ldap://ldap.example.com/o=My%20Organisation - This will perform a LDAP search with the  DN  as
              My Organisation.

              ldap://ldap.example.com/o=My%20Organisation?postalAddress  - This will perform the same search
              but will only return postalAddress attributes.

              ldap://ldap.example.com/?rootDomainNamingContext - This specifies an  empty  DN  and  requests
              information about the rootDomainNamingContext attribute for an Active Directory server.

              For more information about the individual components of a LDAP URL please see RFC4516.

              NOTES

              Starting  with  version  7.20.0,  the fragment part of the URI will not be sent as part of the
              path, which was previously the case.

              CURLOPT_URL is the only option that must be set before curl_easy_perform(3) is called.

              CURLOPT_PROTOCOLS can be used to limit what protocols libcurl  will  use  for  this  transfer,
              independent of what libcurl has been compiled to support. That may be useful if you accept the
              URL from an external source and want to limit the accessibility.

       CURLOPT_PROTOCOLS
              Pass a long that holds a bitmask of CURLPROTO_* defines. If used,  this  bitmask  limits  what
              protocols  libcurl may use in the transfer. This allows you to have a libcurl built to support
              a wide range of protocols but still limit specific transfers to only be allowed to use a  sub-set subset
              set  of  them.  By  default  libcurl  will  accept  all  protocols  it supports. See also CUR-LOPT_REDIR_PROTOCOLS. CURLOPT_REDIR_PROTOCOLS.
              LOPT_REDIR_PROTOCOLS. (Added in 7.19.4)

       CURLOPT_REDIR_PROTOCOLS
              Pass a long that holds a bitmask of CURLPROTO_* defines. If used,  this  bitmask  limits  what
              protocols  libcurl  may  use  in a transfer that it follows to in a redirect when CURLOPT_FOL-LOWLOCATION CURLOPT_FOLLOWLOCATION
              LOWLOCATION is enabled. This allows you to limit specific transfers to only be allowed to  use
              a  subset of protocols in redirections. By default libcurl will allow all protocols except for
              FILE and SCP. This is a difference compared to pre-7.19.4 versions which unconditionally would
              follow to all protocols supported. (Added in 7.19.4)

       CURLOPT_PROXY
              Set  HTTP  proxy  to use. The parameter should be a char * to a zero terminated string holding
              the host name or dotted IP address. To specify port number in this string, append  :[port]  to
              the  end  of the host name. The proxy string may be prefixed with [protocol]:// since any such
              prefix will be ignored. The proxy's port number may optionally be specified with the  separate
              option. If not specified, libcurl will default to using port 1080 for proxies.  CURLOPT_PROXY-PORT. CURLOPT_PROXYPORT.
              PORT.

              When you tell the library to use a HTTP proxy, libcurl will transparently  convert  operations
              to  HTTP even if you specify an FTP URL etc. This may have an impact on what other features of
              the library you can use, such as CURLOPT_QUOTE and  similar  FTP  specifics  that  don't  work
              unless  you tunnel through the HTTP proxy. Such tunneling is activated with CURLOPT_HTTPPROXY-TUNNEL. CURLOPT_HTTPPROXYTUNNEL.
              TUNNEL.

              libcurl respects the environment variables http_proxy, ftp_proxy, all_proxy  etc,  if  any  of
              those  are  set.  The  CURLOPT_PROXY option does however override any possibly set environment
              variables.

              Setting the proxy string to "" (an empty string) will explicitly disable the use of  a  proxy,
              even if there is an environment variable set for it.

              Since  7.14.1, the proxy host string given in environment variables can be specified the exact
              same way as the proxy can be set with CURLOPT_PROXY, include  protocol  prefix  (http://)  and
              embedded user + password.

              Since  7.21.7, the proxy string may be specified with a protocol:// prefix to specify alterna-tive alternative
              tive proxy protocols. Use socks4://, socks4a://, socks5:// or  socks5h://  (the  last  one  to
              enable  socks5  and asking the proxy to do the resolving, also known as CURLPROXY_SOCKS5_HOST-NAME CURLPROXY_SOCKS5_HOSTNAME
              NAME type) to request the specific SOCKS version to be used. No  protocol  specified,  http://
              and all others will be treated as HTTP proxies.

       CURLOPT_PROXYPORT
              Pass a long with this option to set the proxy port to connect to unless it is specified in the
              proxy string CURLOPT_PROXY.

       CURLOPT_PROXYTYPE
              Pass a long with this option to set type of the proxy. Available options for  this  are  CURL-PROXY_HTTP, CURLPROXY_HTTP,
              PROXY_HTTP,  CURLPROXY_HTTP_1__  (added  in  7.19.4),  CURLPROXY_SOCKS4 (added in 7.10), CURL-PROXY_SOCKS5, CURLPROXY_SOCKS5,
              PROXY_SOCKS5, CURLPROXY_SOCKS4A (added in  7.18.0)  and  CURLPROXY_SOCKS5_HOSTNAME  (added  in
              7.18.0). The HTTP type is default. (Added in 7.10)

              If  you set CURLOPT_PROXYTYPE to CURLPROXY_HTTP_1__, it will only affect how libcurl speaks to
              a proxy when CONNECT is used. The HTTP version used for "regular"  HTTP  requests  is  instead
              controlled with CURLOPT_HTTP_VERSION.

       CURLOPT_NOPROXY
              Pass  a  pointer to a zero terminated string. The string consists of a comma separated list of
              host names that do not require a proxy to get reached, even if one  is  specified.   The  only
              wildcard  available is a single * character, which matches all hosts, and effectively disables
              the proxy. Each name in this list is matched as either a domain which contains  the  hostname,
              or  the hostname itself. For example, example.com would match example.com, example.com:80, and
              www.example.com, but not www.notanexample.com.  (Added in 7.19.4)

       CURLOPT_HTTPPROXYTUNNEL
              Set the parameter to 1 to make the library tunnel all operations through a given  HTTP  proxy.
              There  is  a  big difference between using a proxy and to tunnel through it. If you don't know
              what this means, you probably don't want this tunneling option.

       CURLOPT_SOCKS5_GSSAPI_SERVICE
              Pass a char * as parameter to a string holding the name of the service.  The  default  service
              name  for  a SOCKS5 server is rcmd/server-fqdn. This option allows you to change it. (Added in
              7.19.4)

       CURLOPT_SOCKS5_GSSAPI_NEC
              Pass a long set to 1 to enable or 0 to disable. As part of the gssapi negotiation a protection
              mode  is  negotiated.  The RFC1961 says in section 4.3/4.4 it should be protected, but the NEC
              reference implementation does not.  If enabled, this option allows the unprotected exchange of
              the protection mode negotiation. (Added in 7.19.4).

       CURLOPT_INTERFACE
              Pass a char * as parameter. This sets the interface name to use as outgoing network interface.
              The name can be an interface name, an IP address, or a host name.

              Starting with 7.24.0: If the parameter starts with "if!" then it is treated as only as  inter-face interface
              face name and no attempt will ever be named to do treat it as an IP address or to do name res-olution resolution
              olution on it.  If the parameter starts with "host!" it is treated as either an IP address  or
              a hostname.  Hostnames are resolved synchronously.  Using the if! format is highly recommended
              when using the multi interfaces to avoid allowing the code to block.  If  "if!"  is  specified
              but the parameter does not match an existing interface, CURLE_INTERFACE_FAILED is returned.

       CURLOPT_LOCALPORT
              Pass  a  long.  This sets the local port number of the socket used for connection. This can be
              used in combination with CURLOPT_INTERFACE and you are recommended  to  use  CURLOPT_LOCALPOR-TRANGE CURLOPT_LOCALPORTRANGE
              TRANGE as well when this is set. Valid port numbers are 1 - 65535. (Added in 7.15.2)

       CURLOPT_LOCALPORTRANGE
              Pass  a  long.  This  is the number of attempts libcurl will make to find a working local port
              number. It starts with the given CURLOPT_LOCALPORT and adds one to the number for each  retry.
              Setting  this  to 1 or below will make libcurl do only one try for the exact port number. Port
              numbers by nature are scarce resources that will be busy at times so  setting  this  value  to
              something too low might cause unnecessary connection setup failures. (Added in 7.15.2)

       CURLOPT_DNS_CACHE_TIMEOUT
              Pass  a  long, this sets the timeout in seconds. Name resolves will be kept in memory for this
              number of seconds. Set to zero to completely disable caching, or set to -1 to make the  cached
              entries remain forever. By default, libcurl caches this info for 60 seconds.

              The  name resolve functions of various libc implementations don't re-read name server informa-tion information
              tion unless explicitly told so (for example, by calling res_init(3)). This may  cause  libcurl
              to  keep  using  the  older server even if DHCP has updated the server info, and this may look
              like a DNS cache issue to the casual libcurl-app user.

       CURLOPT_DNS_USE_GLOBAL_CACHE
              Pass a long. If the value is 1, it tells curl to use a global  DNS  cache  that  will  survive
              between  easy  handle  creations  and  deletions.  This is not thread-safe and this will use a
              global variable.

              WARNING: this option is considered obsolete. Stop using it. Switch over  to  using  the  share
              interface instead! See CURLOPT_SHARE and curl_share_init(3).

       CURLOPT_BUFFERSIZE
              Pass  a long specifying your preferred size (in bytes) for the receive buffer in libcurl.  The
              main point of this would be that the write callback gets called more often  and  with  smaller
              chunks.  This is just treated as a request, not an order. You cannot be guaranteed to actually
              get the given size. (Added in 7.10)

              This size is by default set as big as possible (CURL_MAX_WRITE_SIZE), so it only  makes  sense
              to use this option if you want it smaller.

       CURLOPT_PORT
              Pass  a long specifying what remote port number to connect to, instead of the one specified in
              the URL or the default port for the used protocol.

       CURLOPT_TCP_NODELAY
              Pass a long specifying whether the TCP_NODELAY option is to be set or cleared (1 =  set,  0  =
              clear).  The  option  is cleared by default. This will have no effect after the connection has
              been established.

              Setting this option will disable TCP's Nagle algorithm. The purpose of this  algorithm  is  to
              try  to  minimize  the number of small packets on the network (where "small packets" means TCP
              segments less than the Maximum Segment Size (MSS) for the network).

              Maximizing the amount of data sent per TCP segment is good because it amortizes  the  overhead
              of the send. However, in some cases (most notably telnet or rlogin) small segments may need to
              be sent without delay. This is less efficient than sending larger amounts of data at  a  time,
              and can contribute to congestion on the network if overdone.

       CURLOPT_ADDRESS_SCOPE
              Pass  a  long specifying the scope_id value to use when connecting to IPv6 link-local or site-local sitelocal
              local addresses. (Added in 7.19.0)

       CURLOPT_TCP_KEEPALIVE
              Pass a long. If set to 1, TCP keepalive probes will be sent. The delay and frequency of  these
              probes  can  be controlled by the CURLOPT_TCP_KEEPIDLE and CURLOPT_TCP_KEEPINTVL options, pro-vided provided
              vided the operating system supports them. Set to 0 (default  behavior)  to  disable  keepalive
              probes (Added in 7.25.0).

       CURLOPT_TCP_KEEPIDLE
              Pass a long. Sets the delay, in seconds, that the operating system will wait while the connec-tion connection
              tion is idle before sending keepalive probes. Not all operating systems support  this  option.
              (Added in 7.25.0)

       CURLOPT_TCP_KEEPINTVL
              Pass  a long. Sets the interval, in seconds, that the operating system will wait between send-ing sending
              ing keepalive probes. Not all operating systems support this option. (Added in 7.25.0)

NAMES and PASSWORDS OPTIONS (Authentication)
       CURLOPT_NETRC
              This parameter controls the preference of libcurl between using user names and passwords  from
              your ~/.netrc file, relative to user names and passwords in the URL supplied with CURLOPT_URL.

              libcurl uses a user name (and supplied or prompted password) supplied with CURLOPT_USERPWD  in
              preference to any of the options controlled by this parameter.

              Pass a long, set to one of the values described below.

              CURL_NETRC_OPTIONAL
                     The  use  of  your  ~/.netrc file is optional, and information in the URL is to be pre-ferred. preferred.
                     ferred.  The file will be scanned for the host and user  name  (to  find  the  password
                     only)  or  for  the  host  only,  to  find  the first user name and password after that
                     machine, which ever information is not specified in the URL.

                     Undefined values of the option will have this effect.

              CURL_NETRC_IGNORED
                     The library will ignore the file and use only the information in the URL.

                     This is the default.

              CURL_NETRC_REQUIRED
                     This value tells the library that use of the file is required, to ignore  the  informa-tion information
                     tion in the URL, and to search the file for the host only.
       Only  machine  name,  user  name  and password are taken into account (init macros and similar things
       aren't supported).

       libcurl does not verify that the file has the correct properties set (as the standard Unix ftp client
       does). It should only be readable by user.

       CURLOPT_NETRC_FILE
              Pass a char * as parameter, pointing to a zero terminated string containing the full path name
              to the file you want libcurl to use as .netrc file.  If  this  option  is  omitted,  and  CUR-LOPT_NETRC CURLOPT_NETRC
              LOPT_NETRC  is  set,  libcurl  will  attempt  to find a .netrc file in the current user's home
              directory. (Added in 7.10.9)

       CURLOPT_USERPWD
              Pass a char * as parameter, which should be [user name]:[password] to use for the  connection.
              Use CURLOPT_HTTPAUTH to decide the authentication method.

              When  using  NTLM, you can set the domain by prepending it to the user name and separating the
              domain and name with a forward (/) or backward slash (\). Like this: "domain/user:password" or
              "domain\user:password".  Some  HTTP  servers  (on  Windows)  support this style even for Basic
              authentication.

              When using HTTP and CURLOPT_FOLLOWLOCATION, libcurl might perform several requests to possibly
              different  hosts. libcurl will only send this user and password information to hosts using the
              initial host name (unless CURLOPT_UNRESTRICTED_AUTH is set), so if libcurl  follows  locations
              to  other  hosts  it will not send the user and password to those. This is enforced to prevent
              accidental information leakage.

       CURLOPT_PROXYUSERPWD
              Pass a char * as parameter, which should be [user name]:[password] to use for  the  connection
              to the HTTP proxy.  Use CURLOPT_PROXYAUTH to decide the authentication method.

       CURLOPT_USERNAME
              Pass  a  char * as parameter, which should be pointing to the zero terminated user name to use
              for the transfer.

              CURLOPT_USERNAME sets the user name to be used in protocol authentication. You should not  use
              this option together with the (older) CURLOPT_USERPWD option.

              In  order  to  specify  the password to be used in conjunction with the user name use the CUR-LOPT_PASSWORD CURLOPT_PASSWORD
              LOPT_PASSWORD option.  (Added in 7.19.1)

       CURLOPT_PASSWORD
              Pass a char * as parameter, which should be pointing to the zero terminated  password  to  use
              for the transfer.

              The  CURLOPT_PASSWORD  option  should be used in conjunction with the CURLOPT_USERNAME option.
              (Added in 7.19.1)

       CURLOPT_PROXYUSERNAME
              Pass a char * as parameter, which should be pointing to the zero terminated user name  to  use
              for the transfer while connecting to Proxy.

              The  CURLOPT_PROXYUSERNAME  option  should  be used in same way as the CURLOPT_PROXYUSERPWD is
              used.  In comparison to CURLOPT_PROXYUSERPWD the CURLOPT_PROXYUSERNAME allows the username  to
              contain a colon, like in the following example: "sip:user@example.com". The CURLOPT_PROXYUSER-NAME CURLOPT_PROXYUSERNAME
              NAME option is an alternative way to set the user name while connecting to Proxy.  There is no
              meaning to use it together with the CURLOPT_PROXYUSERPWD option.

              In  order  to  specify  the password to be used in conjunction with the user name use the CUR-LOPT_PROXYPASSWORD CURLOPT_PROXYPASSWORD
              LOPT_PROXYPASSWORD option.  (Added in 7.19.1)

       CURLOPT_PROXYPASSWORD
              Pass a char * as parameter, which should be pointing to the zero terminated  password  to  use
              for the transfer while connecting to Proxy.

              The  CURLOPT_PROXYPASSWORD option should be used in conjunction with the CURLOPT_PROXYUSERNAME
              option. (Added in 7.19.1)

       CURLOPT_HTTPAUTH
              Pass a long as parameter, which is set to a bitmask,  to  tell  libcurl  which  authentication
              method(s)  you  want  it  to use. The available bits are listed below. If more than one bit is
              set, libcurl will first query the site to see which authentication  methods  it  supports  and
              then  pick  the best one you allow it to use. For some methods, this will induce an extra net-work network
              work round-trip. Set the actual name and password with the CURLOPT_USERPWD option or with  the
              CURLOPT_USERNAME and the CURLOPT_PASSWORD options.  (Added in 7.10.6)

              CURLAUTH_BASIC
                     HTTP  Basic  authentication. This is the default choice, and the only method that is in
                     wide-spread use and supported virtually everywhere. This sends the user name and  pass-word password
                     word over the network in plain text, easily captured by others.

              CURLAUTH_DIGEST
                     HTTP  Digest authentication.  Digest authentication is defined in RFC2617 and is a more
                     secure way to do authentication over public networks  than  the  regular  old-fashioned
                     Basic method.

              CURLAUTH_DIGEST_IE
                     HTTP  Digest  authentication  with  an  IE flavor.  Digest authentication is defined in
                     RFC2617 and is a more secure way to do authentication over  public  networks  than  the
                     regular  old-fashioned  Basic  method.  The IE flavor is simply that libcurl will use a
                     special "quirk" that IE is known to have used before version 7 and  that  some  servers
                     require the client to use. (This define was added in 7.19.3)

              CURLAUTH_GSSNEGOTIATE
                     HTTP  GSS-Negotiate authentication. The GSS-Negotiate (also known as plain "Negotiate")
                     method was designed by Microsoft and is used in their web applications. It is primarily
                     meant  as  a support for Kerberos5 authentication but may also be used along with other
                     authentication methods.  For  more  information  see  IETF  draft  draft-brezak-spnego-http-04.txt. draft-brezak-spnegohttp-04.txt.
                     http-04.txt.

                     You need to build libcurl with a suitable GSS-API library for this to work.

              CURLAUTH_NTLM
                     HTTP  NTLM  authentication.  A  proprietary protocol invented and used by Microsoft. It
                     uses a challenge-response and hash concept similar to Digest, to prevent  the  password
                     from being eavesdropped.

                     You need to build libcurl with either OpenSSL, GnuTLS or NSS support for this option to
                     work, or build libcurl on Windows.

              CURLAUTH_NTLM_WB
                     NTLM delegating to winbind helper. Authentication is performed  by  a  separate  binary
                     application  that  is executed when needed. The name of the application is specified at
                     compile time but is typically /usr/bin/ntlm_auth (Added in 7.22.0)

                     Note that libcurl will fork when necessary to run the winbind application and  kill  it
                     when  complete,  calling waitpid() to await its exit when done. On POSIX operating sys-tems, systems,
                     tems, killing the process will cause a SIGCHLD  signal  to  be  raised  (regardless  of
                     whether  CURLOPT_NOSIGNAL  is set), which must be handled intelligently by the applica-tion. application.
                     tion. In particular, the application  must  not  unconditionally  call  wait()  in  its
                     SIGCHLD  signal  handler  to avoid being subject to a race condition.  This behavior is
                     subject to change in future versions of libcurl.

              CURLAUTH_ANY
                     This is a convenience macro that sets all bits and thus makes libcurl pick any it finds
                     suitable. libcurl will automatically select the one it finds most secure.

              CURLAUTH_ANYSAFE
                     This is a convenience macro that sets all bits except Basic and thus makes libcurl pick
                     any it finds suitable. libcurl will automatically select the one it finds most  secure.

              CURLAUTH_ONLY
                     This  is  a  meta  symbol.  Or this value together with a single specific auth value to
                     force libcurl to probe for un-restricted auth and if not, only that single  auth  algo-rithm algorithm
                     rithm is acceptable. (Added in 7.21.3)

       CURLOPT_TLSAUTH_TYPE
              Pass  a  long  as  parameter,  which is set to a bitmask, to tell libcurl which authentication
              method(s) you want it to use for TLS authentication.

              CURLOPT_TLSAUTH_SRP
                     TLS-SRP authentication. Secure Remote Password authentication for  TLS  is  defined  in
                     RFC5054  and  provides mutual authentication if both sides have a shared secret. To use
                     TLS-SRP, you must also set the  CURLOPT_TLSAUTH_USERNAME  and  CURLOPT_TLSAUTH_PASSWORD
                     options.

                     You need to build libcurl with GnuTLS or OpenSSL with TLS-SRP support for this to work.
                     (Added in 7.21.4)

       CURLOPT_TLSAUTH_USERNAME
              Pass a char * as parameter, which should point to the zero terminated username to use for  the
              TLS  authentication  method  specified with the CURLOPT_TLSAUTH_TYPE option. Requires that the
              CURLOPT_TLS_PASSWORD option also be set. (Added in 7.21.4)

       CURLOPT_TLSAUTH_PASSWORD
              Pass a char * as parameter, which should point to the zero terminated password to use for  the
              TLS  authentication  method  specified with the CURLOPT_TLSAUTH_TYPE option. Requires that the
              CURLOPT_TLS_USERNAME option also be set. (Added in 7.21.4)

       CURLOPT_PROXYAUTH
              Pass a long as parameter, which is set to a bitmask,  to  tell  libcurl  which  authentication
              method(s)  you  want  it  to  use for your proxy authentication.  If more than one bit is set,
              libcurl will first query the site to see what authentication methods it supports and then pick
              the  best  one you allow it to use. For some methods, this will induce an extra network round-trip. roundtrip.
              trip. Set the actual name and password with the CURLOPT_PROXYUSERPWD option. The  bitmask  can
              be constructed by or'ing together the bits listed above for the CURLOPT_HTTPAUTH option. As of
              this writing, only Basic, Digest and NTLM work. (Added in 7.10.7)

HTTP OPTIONS
       CURLOPT_AUTOREFERER
              Pass a parameter set to 1 to enable this. When enabled, libcurl  will  automatically  set  the
              Referer: field in requests where it follows a Location: redirect.

       CURLOPT_ACCEPT_ENCODING
              Sets  the contents of the Accept-Encoding: header sent in a HTTP request, and enables decoding
              of a response when a Content-Encoding: header is received.   Three  encodings  are  supported:
              identity, which does nothing, deflate which requests the server to compress its response using
              the zlib algorithm, and gzip which requests the gzip algorithm.  If a  zero-length  string  is
              set, then an Accept-Encoding: header containing all supported encodings is sent.

              This is a request, not an order; the server may or may not do it.  This option must be set (to
              any non-NULL value) or else any unsolicited encoding done by the server is  ignored.  See  the
              special file lib/README.encoding for details.

              (This option was called CURLOPT_ENCODING before 7.21.6)

       CURLOPT_TRANSFER_ENCODING
              Adds  a  request  for compressed Transfer Encoding in the outgoing HTTP request. If the server
              supports this and so desires, it can respond with the HTTP response sent  using  a  compressed
              Transfer-Encoding that will be automatically uncompressed by libcurl on reception.

              Transfer-Encoding   differs   slightly  from  the  Content-Encoding  you  ask  for  with  CUR-LOPT_ACCEPT_ENCODING CURLOPT_ACCEPT_ENCODING
              LOPT_ACCEPT_ENCODING in that a Transfer-Encoding is strictly meant to be for the transfer  and
              thus  MUST  be decoded before the data arrives in the client. Traditionally, Transfer-Encoding
              has been much less used and supported by both HTTP clients and HTTP servers.

              (Added in 7.21.6)

       CURLOPT_FOLLOWLOCATION
              A parameter set to 1 tells the library to follow any Location: header that the server sends as
              part of a HTTP header.

              This  means  that the library will re-send the same request on the new location and follow new
              Location: headers all the way until no more such headers are returned.  CURLOPT_MAXREDIRS  can
              be used to limit the number of redirects libcurl will follow.

              Since 7.19.4, libcurl can limit what protocols it will automatically follow. The accepted pro-tocols protocols
              tocols are set with CURLOPT_REDIR_PROTOCOLS and it excludes the FILE protocol by default.

       CURLOPT_UNRESTRICTED_AUTH
              A parameter set to 1 tells the library it can continue to send authentication  (user+password)
              when following locations, even when hostname changed. This option is meaningful only when set-ting setting
              ting CURLOPT_FOLLOWLOCATION.

       CURLOPT_MAXREDIRS
              Pass a long. The set number will be the redirection limit. If that many redirections have been
              followed,  the  next redirect will cause an error (CURLE_TOO_MANY_REDIRECTS). This option only
              makes sense if the CURLOPT_FOLLOWLOCATION is used at the same time. Added in  7.15.1:  Setting
              the  limit  to 0 will make libcurl refuse any redirect. Set it to -1 for an infinite number of
              redirects (which is the default)

       CURLOPT_POSTREDIR
              Pass a bitmask to control how libcurl acts on redirects after POSTs that get a 301, 302 or 303
              response  back.   A  parameter with bit 0 set (value CURL_REDIR_POST_301) tells the library to
              respect RFC2616/10.3.2 and not convert POST requests into GET requests when  following  a  301
              redirection.   Setting  bit  1  (value CURL_REDIR_POST_302) makes libcurl maintain the request
              method after a 302 redirect whilst setting bit 2  (value  CURL_REDIR_POST_303)  makes  libcurl
              maintain  the  request  method after a 303 redirect. The value CURL_REDIR_POST_ALL is a conve-nience convenience
              nience define that sets all three bits.

              The non-RFC behaviour is ubiquitous in web browsers, so the library  does  the  conversion  by
              default  to  maintain consistency. However, a server may require a POST to remain a POST after
              such a redirection. This  option  is  meaningful  only  when  setting  CURLOPT_FOLLOWLOCATION.
              (Added  in 7.17.1) (This option was known as CURLOPT_POST301 up to 7.19.0 as it only supported
              the 301 then)

       CURLOPT_PUT
              A parameter set to 1 tells the library to use HTTP PUT to transfer data. The  data  should  be
              set with CURLOPT_READDATA and CURLOPT_INFILESIZE.

              This  option  is  deprecated  and  starting  with  version  7.12.1 you should instead use CUR-LOPT_UPLOAD. CURLOPT_UPLOAD.
              LOPT_UPLOAD.

       CURLOPT_POST
              A parameter set to 1 tells the library to do a regular HTTP post.  This  will  also  make  the
              library  use  a  "Content-Type: application/x-www-form-urlencoded" header. (This is by far the
              most commonly used POST method).

              Use one of CURLOPT_POSTFIELDS or CURLOPT_COPYPOSTFIELDS options to specify what data  to  post
              and CURLOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE to set the data size.

              Optionally,  you  can provide data to POST using the CURLOPT_READFUNCTION and CURLOPT_READDATA
              options but then you must make sure to not set CURLOPT_POSTFIELDS to anything but  NULL.  When
              providing  data  with  a callback, you must transmit it using chunked transfer-encoding or you
              must set the size of the data with the  CURLOPT_POSTFIELDSIZE  or  CURLOPT_POSTFIELDSIZE_LARGE
              option.  To  enable  chunked  encoding,  you  simply pass in the appropriate Transfer-Encoding
              header, see the post-callback.c example.

              You can override the default POST Content-Type: header by setting your own with  CURLOPT_HTTP-HEADER. CURLOPT_HTTPHEADER.
              HEADER.

              Using  POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.  You can disable
              this header with CURLOPT_HTTPHEADER as usual.

              If you use POST to a HTTP 1.1 server, you can send data without knowing the size before start-ing starting
              ing  the  POST if you use chunked encoding. You enable this by adding a header like "Transfer-Encoding: "TransferEncoding:
              Encoding: chunked" with CURLOPT_HTTPHEADER. With HTTP 1.0 or  without  chunked  transfer,  you
              must specify the size in the request.

              When  setting CURLOPT_POST to 1, it will automatically set CURLOPT_NOBODY to 0 (since 7.14.1).

              If you issue a POST request and then want to make a HEAD or GET using the same re-used handle,
              you  must explicitly set the new request type using CURLOPT_NOBODY or CURLOPT_HTTPGET or simi-lar. similar.
              lar.

       CURLOPT_POSTFIELDS
              Pass a void * as parameter, which should be the full data to post in a  HTTP  POST  operation.
              You  must  make  sure  that  the  data is formatted the way you want the server to receive it.
              libcurl will not convert or encode it for you. Most web servers will assume this  data  to  be
              url-encoded.

              The  pointed  data  are NOT copied by the library: as a consequence, they must be preserved by
              the calling application until the transfer finishes.

              This POST is a normal application/x-www-form-urlencoded kind (and libcurl will set  that  Con-tent-Type Content-Type
              tent-Type  by  default  when this option is used), which is the most commonly used one by HTML
              forms. See also the CURLOPT_POST. Using CURLOPT_POSTFIELDS implies CURLOPT_POST.

              If you want to do a zero-byte POST, you need to set CURLOPT_POSTFIELDSIZE explicitly to  zero,
              as  simply  setting  CURLOPT_POSTFIELDS to NULL or "" just effectively disables the sending of
              the specified string. libcurl will instead assume that you'll send the  POST  data  using  the
              read callback!

              Using  POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.  You can disable
              this header with CURLOPT_HTTPHEADER as usual.

              To make multipart/formdata posts (aka RFC2388-posts), check out the CURLOPT_HTTPPOST option.

       CURLOPT_POSTFIELDSIZE
              If you want to post data to the server without letting libcurl do a strlen()  to  measure  the
              data  size, this option must be used. When this option is used you can post fully binary data,
              which otherwise is likely to fail. If this size is set to -1, the library will use strlen() to
              get the size.

       CURLOPT_POSTFIELDSIZE_LARGE
              Pass  a  curl_off_t  as  parameter. Use this to set the size of the CURLOPT_POSTFIELDS data to
              prevent libcurl from doing strlen() on the data to figure out the size. This is the large file
              version of the CURLOPT_POSTFIELDSIZE option. (Added in 7.11.1)

       CURLOPT_COPYPOSTFIELDS
              Pass a char * as parameter, which should be the full data to post in a HTTP POST operation. It
              behaves as the CURLOPT_POSTFIELDS option, but the original data are  copied  by  the  library,
              allowing the application to overwrite the original data after setting this option.

              Because  data  are  copied, care must be taken when using this option in conjunction with CUR-LOPT_POSTFIELDSIZE CURLOPT_POSTFIELDSIZE
              LOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE: If the size has not been set prior to  CUR-LOPT_COPYPOSTFIELDS, CURLOPT_COPYPOSTFIELDS,
              LOPT_COPYPOSTFIELDS,  the data are assumed to be a NUL-terminated string; else the stored size
              informs the library about the data byte count to copy. In any  case,  the  size  must  not  be
              changed  after  CURLOPT_COPYPOSTFIELDS, unless another CURLOPT_POSTFIELDS or CURLOPT_COPYPOST-FIELDS CURLOPT_COPYPOSTFIELDS
              FIELDS option is issued.  (Added in 7.17.1)

       CURLOPT_HTTPPOST
              Tells libcurl you want a multipart/formdata HTTP POST to be made and you instruct what data to
              pass on to the server.  Pass a pointer to a linked list of curl_httppost structs as parameter.
              The easiest way to create such a list, is to use curl_formadd(3) as documented.  The  data  in
              this list must remain intact until you close this curl handle again with curl_easy_cleanup(3).

              Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.  You can  disable
              this header with CURLOPT_HTTPHEADER as usual.

              When setting CURLOPT_HTTPPOST, it will automatically set CURLOPT_NOBODY to 0 (since 7.14.1).

       CURLOPT_REFERER
              Pass  a  pointer to a zero terminated string as parameter. It will be used to set the Referer:
              header in the http request sent to the remote server. This can be  used  to  fool  servers  or
              scripts. You can also set any custom header with CURLOPT_HTTPHEADER.

       CURLOPT_USERAGENT
              Pass  a  pointer  to  a  zero terminated string as parameter. It will be used to set the User-Agent: UserAgent:
              Agent: header in the http request sent to the remote server. This can be used to fool  servers
              or scripts. You can also set any custom header with CURLOPT_HTTPHEADER.

       CURLOPT_HTTPHEADER
              Pass  a  pointer  to a linked list of HTTP headers to pass to the server in your HTTP request.
              The linked list should be a fully valid list of struct curl_slist structs properly filled  in.
              Use  curl_slist_append(3)  to create the list and curl_slist_free_all(3) to clean up an entire
              list. If you add a header that is otherwise generated and used  by  libcurl  internally,  your
              added  one  will be used instead. If you add a header with no content as in 'Accept:' (no data
              on the right side of the colon), the internally used header will  get  disabled.  Thus,  using
              this  option you can add new headers, replace internal headers and remove internal headers. To
              add a header with no content, make the content be two quotes: "". The headers included in  the
              linked  list must not be CRLF-terminated, because curl adds CRLF after each header item. Fail-ure Failure
              ure to comply with this will result in strange bugs because the server will most likely ignore
              part of the headers you specified.

              The first line in a request (containing the method, usually a GET or POST) is not a header and
              cannot be replaced using this option. Only the lines following the request-line  are  headers.
              Adding  this  method  line  in  this  list  of headers will only cause your request to send an
              invalid header.

              Pass a NULL to this to reset back to no custom headers.

              The most commonly replaced headers  have  "shortcuts"  in  the  options  CURLOPT_COOKIE,  CUR-LOPT_USERAGENT CURLOPT_USERAGENT
              LOPT_USERAGENT and CURLOPT_REFERER.

       CURLOPT_HTTP200ALIASES
              Pass  a  pointer  to a linked list of aliases to be treated as valid HTTP 200 responses.  Some
              servers respond with a custom header response line.  For example, IceCast servers respond with
              "ICY  200 OK".  By including this string in your list of aliases, the response will be treated
              as a valid HTTP header line such as "HTTP/1.0 200 OK". (Added in 7.10.3)

              The linked list should be a fully valid list of struct curl_slist  structs,  and  be  properly
              filled in.  Use curl_slist_append(3) to create the list and curl_slist_free_all(3) to clean up
              an entire list.

              The alias itself is not parsed for any version strings. Before libcurl  7.16.3,  Libcurl  used
              the value set by option CURLOPT_HTTP_VERSION, but starting with 7.16.3 the protocol is assumed
              to match HTTP 1.0 when an alias matched.

       CURLOPT_COOKIE
              Pass a pointer to a zero terminated string as parameter. It will be used to set  a  cookie  in
              the  http  request. The format of the string should be NAME=CONTENTS, where NAME is the cookie
              name and CONTENTS is what the cookie should contain.

              If you need to set multiple cookies, you need to set them all using a single option  and  thus
              you need to concatenate them all in one single string. Set multiple cookies in one string like
              this: "name1=content1; name2=content2;" etc.

              This option sets the cookie header explicitly in the outgoing request(s). If multiple requests
              are  done  due  to  authentication,  followed  redirections or similar, they will all get this
              cookie passed on.

              Using this option multiple times will only make the latest string override the previous  ones.

       CURLOPT_COOKIEFILE
              Pass  a  pointer  to a zero terminated string as parameter. It should contain the name of your
              file holding cookie data to read. The cookie data may be in Netscape  /  Mozilla  cookie  data
              format or just regular HTTP-style headers dumped to a file.

              Given  an  empty  or  non-existing  file or by passing the empty string (""), this option will
              enable cookies for this curl handle, making it understand and parse received cookies and  then
              use matching cookies in future requests.

              If you use this option multiple times, you just add more files to read.  Subsequent files will
              add more cookies.

       CURLOPT_COOKIEJAR
              Pass a file name as char *, zero terminated. This will make libcurl write all internally known
              cookies to the specified file when curl_easy_cleanup(3) is called. If no cookies are known, no
              file will be created. Specify "-" to instead have the cookies written to  stdout.  Using  this
              option  also enables cookies for this session, so if you for example follow a location it will
              make matching cookies get sent accordingly.

              If the cookie jar file can't be created  or  written  to  (when  the  curl_easy_cleanup(3)  is
              called),  libcurl  will not and cannot report an error for this. Using CURLOPT_VERBOSE or CUR-LOPT_DEBUGFUNCTION CURLOPT_DEBUGFUNCTION
              LOPT_DEBUGFUNCTION will get a warning to display, but that is the only  visible  feedback  you
              get about this possibly lethal situation.

       CURLOPT_COOKIESESSION
              Pass  a  long set to 1 to mark this as a new cookie "session". It will force libcurl to ignore
              all cookies it is about to load that are "session  cookies"  from  the  previous  session.  By
              default,  libcurl always stores and loads all cookies, independent if they are session cookies
              or not. Session cookies are cookies without expiry date and they are meant  to  be  alive  and
              existing for this "session" only.

       CURLOPT_COOKIELIST
              Pass  a  char  * to a cookie string. Cookie can be either in Netscape / Mozilla format or just
              regular HTTP-style header (Set-Cookie: ...) format. If cURL cookie engine was not  enabled  it
              will  enable  its cookie engine.  Passing a magic string "ALL" will erase all cookies known by
              cURL. (Added in 7.14.1) Passing the special string "SESS" will only erase all session  cookies
              known  by  cURL.  (Added  in 7.15.4) Passing the special string "FLUSH" will write all cookies
              known by cURL to the file specified by CURLOPT_COOKIEJAR.  (Added in 7.17.1)

       CURLOPT_HTTPGET
              Pass a long. If the long is 1, this forces the HTTP request to get back to GET.  Usable  if  a
              POST, HEAD, PUT, or a custom request has been used previously using the same curl handle.

              When  setting  CURLOPT_HTTPGET  to  1,  it will automatically set CURLOPT_NOBODY to 0 and CUR-LOPT_UPLOAD CURLOPT_UPLOAD
              LOPT_UPLOAD to 0.

       CURLOPT_HTTP_VERSION
              Pass a long, set to one of the values described below. They force libcurl to use the  specific
              HTTP versions. This is not sensible to do unless you have a good reason.

              CURL_HTTP_VERSION_NONE
                     We  don't care about what version the library uses. libcurl will use whatever it thinks
                     fit.

              CURL_HTTP_VERSION_1_0
                     Enforce HTTP 1.0 requests.

              CURL_HTTP_VERSION_1_1
                     Enforce HTTP 1.1 requests.

       CURLOPT_IGNORE_CONTENT_LENGTH
              Ignore the Content-Length header. This is useful for Apache 1.x (and  similar  servers)  which
              will  report incorrect content length for files over 2 gigabytes. If this option is used, curl
              will not be able to accurately report progress, and will simply stop  the  download  when  the
              server ends the connection. (added in 7.14.1)

       CURLOPT_HTTP_CONTENT_DECODING
              Pass  a  long to tell libcurl how to act on content decoding. If set to zero, content decoding
              will be disabled. If set to 1 it is enabled. Libcurl  has  no  default  content  decoding  but
              requires you to use CURLOPT_ACCEPT_ENCODING for that. (added in 7.16.2)

       CURLOPT_HTTP_TRANSFER_DECODING
              Pass a long to tell libcurl how to act on transfer decoding. If set to zero, transfer decoding
              will be disabled, if set to 1 it is enabled (default). libcurl does chunked transfer  decoding
              by default unless this option is set to zero. (added in 7.16.2)

SMTP OPTIONS
       CURLOPT_MAIL_FROM
              Pass  a  pointer  to a zero terminated string as parameter. This should be used to specify the
              sender's email address when sending SMTP mail with libcurl.

              An originator email address should be specified with angled brackets (<>) around it, which  if
              not  specified,  will be added by libcurl from version 7.21.4 onwards. Failing to provide such
              brackets may cause the server to reject the email.

              If this parameter is not specified then an empty address will be sent to the mail server which
              may or may not cause the email to be rejected.

              (Added in 7.20.0)

       CURLOPT_MAIL_RCPT
              Pass a pointer to a linked list of recipients to pass to the server in your SMTP mail request.
              The linked list should be a fully valid list of struct curl_slist structs properly filled  in.
              Use  curl_slist_append(3)  to create the list and curl_slist_free_all(3) to clean up an entire
              list.

              Each recipient should be specified within a pair of angled brackets (<>), however, should  you
              not  use  an  angled  bracket as the first character libcurl will assume you provided a single
              email address and enclose that address within brackets for you.

              (Added in 7.20.0)

       CURLOPT_MAIL_AUTH
              Pass a pointer to a zero terminated string as parameter. This will  be  used  to  specify  the
              authentication  address  (identity)  of  a  submitted message that is being relayed to another
              server.

              This optional parameter allows co-operating agents in a trusted environment to communicate the
              authentication  of  individual  messages  and  should only be used by the application program,
              using libcurl, if the application is itself a mail server acting in such  an  environment.  If
              the  application is operating as such and the AUTH address is not known or is invalid, then an
              empty string should be used for this parameter.

              Unlike CURLOPT_MAIL_FROM and CURLOPT_MAIL_RCPT, the address should not be specified  within  a
              pair of angled brackets (<>). However, if an empty string is used then a pair of brackets will
              be sent by libcurl as required by RFC2554.

              (Added in 7.25.0)

TFTP OPTIONS
       CURLOPT_TFTP_BLKSIZE
              Specify block size to use for TFTP data transmission. Valid range as per  RFC2348  is  8-65464
              bytes.  The  default  of 512 bytes will be used if this option is not specified. The specified
              block size will only be used pending support by the remote server.  If  the  server  does  not
              return  an  option  acknowledgement  or returns an option acknowledgement with no blksize, the
              default of 512 bytes will be used. (added in 7.19.4)

FTP OPTIONS
       CURLOPT_FTPPORT
              Pass a pointer to a zero terminated string as parameter. It will be used to get the IP address
              to  use  for the FTP PORT instruction. The PORT instruction tells the remote server to connect
              to our specified IP address. The string may be a plain IP address,  a  host  name,  a  network
              interface  name (under Unix) or just a '-' symbol to let the library use your system's default
              IP address. Default FTP operations are passive, and thus won't use PORT.

              The address can be followed by a ':' to specify a port, optionally followed by a '-' to  spec-ify specify
              ify a port range.  If the port specified is 0, the operating system will pick a free port.  If
              a range is provided and all ports  in  the  range  are  not  available,  libcurl  will  report
              CURLE_FTP_PORT_FAILED  for  the  handle.   Invalid  port/range  settings  are  ignored.   IPv6
              addresses followed by a port or portrange have to be  in  brackets.   IPv6  addresses  without
              port/range specifier can be in brackets.  (added in 7.19.5)

              Examples with specified ports:

                eth0:0
                192.168.1.2:32000-33000
                curl.se:32123
                [::1]:1234-4567

              You  disable  PORT  again  and  go back to using the passive version by setting this option to
              NULL.

       CURLOPT_QUOTE
              Pass a pointer to a linked list of FTP or SFTP commands to pass to the server  prior  to  your
              FTP  request. This will be done before any other commands are issued (even before the CWD com-mand command
              mand for FTP). The linked list should be a fully valid list  of  'struct  curl_slist'  structs
              properly filled in with text strings. Use curl_slist_append(3) to append strings (commands) to
              the list, and clear the entire list afterwards with curl_slist_free_all(3). Disable this oper-ation operation
              ation  again  by  setting a NULL to this option. When speaking to a FTP (or SFTP since 7.24.0)
              server, prefix the command with an asterisk (*) to make libcurl continue even if  the  command
              fails as by default libcurl will stop at first failure.

              The  set  of valid FTP commands depends on the server (see RFC959 for a list of mandatory com-mands). commands).
              mands).

              The valid SFTP commands are: chgrp, chmod, chown, ln, mkdir, pwd, rename, rm,  rmdir,  symlink
              (see curl(1)) (SFTP support added in 7.16.3)

       CURLOPT_POSTQUOTE
              Pass  a  pointer to a linked list of FTP or SFTP commands to pass to the server after your FTP
              transfer request. The commands will only be run if no error occurred. The linked  list  should
              be  a  fully  valid list of struct curl_slist structs properly filled in as described for CUR-LOPT_QUOTE. CURLOPT_QUOTE.
              LOPT_QUOTE. Disable this operation again by setting a NULL to this option.

       CURLOPT_PREQUOTE
              Pass a pointer to a linked list of FTP commands to pass to the server after the transfer  type
              is  set.  The  linked  list should be a fully valid list of struct curl_slist structs properly
              filled in as described for CURLOPT_QUOTE. Disable this operation again by setting  a  NULL  to
              this  option.  Before  version 7.16.0, if you also set CURLOPT_NOBODY to 1, this option didn't
              work.

       CURLOPT_DIRLISTONLY
              A parameter set to 1 tells the library to just list the names of files in a directory, instead
              of doing a full directory listing that would include file sizes, dates etc. This works for FTP
              and SFTP URLs.

              This causes an FTP NLST command to be sent on an FTP server.  Beware  that  some  FTP  servers
              list  only files in their response to NLST; they might not include subdirectories and symbolic
              links.

              Setting this option to 1 also implies a directory listing even if the URL doesn't end  with  a
              slash, which otherwise is necessary.

              Do NOT use this option if you also use CURLOPT_WILDCARDMATCH as it will effectively break that
              feature then.

              (This option was known as CURLOPT_FTPLISTONLY up to 7.16.4)

       CURLOPT_APPEND
              A parameter set to 1 tells the library to append to the remote file instead of  overwrite  it.
              This is only useful when uploading to an FTP site.

              (This option was known as CURLOPT_FTPAPPEND up to 7.16.4)

       CURLOPT_FTP_USE_EPRT
              Pass  a  long.  If the value is 1, it tells curl to use the EPRT (and LPRT) command when doing
              active FTP downloads (which is enabled by CURLOPT_FTPPORT). Using  EPRT  means  that  it  will
              first  attempt  to  use  EPRT  and  then  LPRT before using PORT, but if you pass zero to this
              option, it will not try using EPRT or LPRT, only plain PORT. (Added in 7.10.5)

              If the server is an IPv6 host, this option will have no effect as of 7.12.3.

       CURLOPT_FTP_USE_EPSV
              Pass a long. If the value is 1, it tells curl to use the EPSV command when doing  passive  FTP
              downloads  (which  it  always does by default). Using EPSV means that it will first attempt to
              use EPSV before using PASV, but if you pass zero to this option, it will not try  using  EPSV,
              only plain PASV.

              If the server is an IPv6 host, this option will have no effect as of 7.12.3.

       CURLOPT_FTP_USE_PRET
              Pass  a  long. If the value is 1, it tells curl to send a PRET command before PASV (and EPSV).
              Certain FTP servers, mainly drftpd, require this non-standard command for  directory  listings
              as  well  as  up and downloads in PASV mode. Has no effect when using the active FTP transfers
              mode.  (Added in 7.20.0)

       CURLOPT_FTP_CREATE_MISSING_DIRS
              Pass a long. If the value is 1, curl will attempt to create any remote directory that it fails
              to CWD into. CWD is the command that changes working directory. (Added in 7.10.7)

              This  setting  also applies to SFTP-connections. curl will attempt to create the remote direc-tory directory
              tory if it can't obtain a handle to the target-location. The creation will fail if a  file  of
              the  same  name as the directory to create already exists or lack of permissions prevents cre-ation. creation.
              ation. (Added in 7.16.3)

              Starting with 7.19.4, you can also set this value to 2, which will make libcurl retry the  CWD
              command  again  if the subsequent MKD command fails. This is especially useful if you're doing
              many simultaneous connections against the same server and they all have this  option  enabled,
              as  then  CWD  may  first fail but then another connection does MKD before this connection and
              thus MKD fails but trying  CWD  works!  7.19.4  also  introduced  the  CURLFTP_CREATE_DIR  and
              CURLFTP_CREATE_DIR_RETRY enum names for these arguments.

              Before  version  7.19.4,  libcurl  will  simply  ignore arguments set to 2 and act as if 1 was
              selected.

       CURLOPT_FTP_RESPONSE_TIMEOUT
              Pass a long.  Causes curl to set a timeout period (in seconds) on the amount of time that  the
              server  is  allowed  to  take in order to generate a response message for a command before the
              session is considered hung.  While curl is waiting for a response, this value  overrides  CUR-LOPT_TIMEOUT. CURLOPT_TIMEOUT.
              LOPT_TIMEOUT. It is recommended that if used in conjunction with CURLOPT_TIMEOUT, you set CUR-LOPT_FTP_RESPONSE_TIMEOUT CURLOPT_FTP_RESPONSE_TIMEOUT
              LOPT_FTP_RESPONSE_TIMEOUT to a value smaller than CURLOPT_TIMEOUT.  (Added in 7.10.8)

       CURLOPT_FTP_ALTERNATIVE_TO_USER
              Pass a char * as parameter, pointing to a string which will be used  to  authenticate  if  the
              usual  FTP  "USER user" and "PASS password" negotiation fails. This is currently only known to
              be required when connecting to Tumbleweed's Secure Transport FTPS server using client certifi-cates certificates
              cates for authentication. (Added in 7.15.5)

       CURLOPT_FTP_SKIP_PASV_IP
              Pass  a  long. If set to 1, it instructs libcurl to not use the IP address the server suggests
              in its 227-response to libcurl's PASV command  when  libcurl  connects  the  data  connection.
              Instead  libcurl  will  re-use the same IP address it already uses for the control connection.
              But it will use the port number from the 227-response. (Added in 7.14.2)

              This option has no effect if PORT, EPRT or EPSV is used instead of PASV.

       CURLOPT_FTPSSLAUTH
              Pass a long using one of the values from below, to alter how  libcurl  issues  "AUTH  TLS"  or
              "AUTH SSL" when FTP over SSL is activated (see CURLOPT_USE_SSL). (Added in 7.12.2)

              CURLFTPAUTH_DEFAULT
                     Allow libcurl to decide.

              CURLFTPAUTH_SSL
                     Try "AUTH SSL" first, and only if that fails try "AUTH TLS".

              CURLFTPAUTH_TLS
                     Try "AUTH TLS" first, and only if that fails try "AUTH SSL".

       CURLOPT_FTP_SSL_CCC
              If  enabled,  this  option  makes  libcurl  use CCC (Clear Command Channel). It shuts down the
              SSL/TLS layer after authenticating. The rest of the  control  channel  communication  will  be
              unencrypted.  This  allows NAT routers to follow the FTP transaction. Pass a long using one of
              the values below.  (Added in 7.16.1)

              CURLFTPSSL_CCC_NONE
                     Don't attempt to use CCC.

              CURLFTPSSL_CCC_PASSIVE
                     Do not initiate the shutdown, but wait for the server to do it. Do not send a reply.

              CURLFTPSSL_CCC_ACTIVE
                     Initiate the shutdown and wait for a reply.

       CURLOPT_FTP_ACCOUNT
              Pass a pointer to a zero terminated string (or NULL to disable). When an FTP server  asks  for
              "account data" after user name and password has been provided, this data is sent off using the
              ACCT command. (Added in 7.13.0)

       CURLOPT_FTP_FILEMETHOD
              Pass a long that should have one of the following values. This  option  controls  what  method
              libcurl  should use to reach a file on a FTP(S) server. The argument should be one of the fol-lowing following
              lowing alternatives:

              CURLFTPMETHOD_MULTICWD
                     libcurl does a single CWD operation for each path part in the given URL. For deep hier-archies hierarchies
                     archies  this  means many commands. This is how RFC1738 says it should be done. This is
                     the default but the slowest behavior.

              CURLFTPMETHOD_NOCWD
                     libcurl does no CWD at all. libcurl will do SIZE, RETR, STOR etc and give a  full  path
                     to the server for all these commands. This is the fastest behavior.

              CURLFTPMETHOD_SINGLECWD
                     libcurl does one CWD with the full target directory and then operates on the file "nor-mally" "normally"
                     mally" (like in the multicwd case). This is  somewhat  more  standards  compliant  than
                     'nocwd' but without the full penalty of 'multicwd'.
       (Added in 7.15.1)

RTSP OPTIONS
       CURLOPT_RTSP_REQUEST
              Tell  libcurl  what  kind of RTSP request to make. Pass one of the following RTSP enum values.
              Unless noted otherwise, commands require the Session ID to be initialized. (Added in 7.20.0)

              CURL_RTSPREQ_OPTIONS
                     Used to retrieve the available methods of the server. The  application  is  responsible
                     for  parsing  and obeying the response. (The session ID is not needed for this method.)
                     (Added in 7.20.0)

              CURL_RTSPREQ_DESCRIBE
                     Used to get the low level description of a stream. The  application  should  note  what
                     formats it understands in the 'Accept:' header. Unless set manually, libcurl will auto-matically automatically
                     matically fill in 'Accept: application/sdp'. Time-condition headers will  be  added  to
                     Describe requests if the CURLOPT_TIMECONDITION option is active. (The session ID is not
                     needed for this method)  (Added in 7.20.0)

              CURL_RTSPREQ_ANNOUNCE
                     When sent by a client, this method changes the description of the session. For example,
                     if  a  client  is  using the server to record a meeting, the client can use Announce to
                     inform the server of all the meta-information about the session.  ANNOUNCE acts like  a
                     HTTP PUT or POST just like CURL_RTSPREQ_SET_PARAMETER (Added in 7.20.0)

              CURL_RTSPREQ_SETUP
                     Setup  is  used to initialize the transport layer for the session. The application must
                     set the desired Transport options for a session  by  using  the  CURLOPT_RTSP_TRANSPORT
                     option prior to calling setup. If no session ID is currently set with CURLOPT_RTSP_SES-SION_ID, CURLOPT_RTSP_SESSION_ID,
                     SION_ID, libcurl will extract and use the session ID in the response to  this  request.
                     (The session ID is not needed for this method).  (Added in 7.20.0)

              CURL_RTSPREQ_PLAY
                     Send  a Play command to the server. Use the CURLOPT_RANGE option to modify the playback
                     time (e.g. 'npt=10-15').  (Added in 7.20.0)

              CURL_RTSPREQ_PAUSE
                     Send a Pause command to the server. Use the CURLOPT_RANGE option with a single value to
                     indicate when the stream should be halted. (e.g. npt='25') (Added in 7.20.0)

              CURL_RTSPREQ_TEARDOWN
                     This command terminates an RTSP session. Simply closing a connection does not terminate
                     the RTSP session since it is valid to control an RTSP session  over  different  connec-tions. connections.
                     tions.  (Added in 7.20.0)

              CURL_RTSPREQ_GET_PARAMETER
                     Retrieve  a parameter from the server. By default, libcurl will automatically include a
                     Content-Type: text/parameters header on all non-empty requests unless a custom  one  is
                     set.  GET_PARAMETER acts just like a HTTP PUT or POST (see CURL_RTSPREQ_SET_PARAMETER).
                     Applications wishing to send a heartbeat message (e.g. in the  presence  of  a  server-specified serverspecified
                     specified timeout) should send use an empty GET_PARAMETER request.  (Added in 7.20.0)

              CURL_RTSPREQ_SET_PARAMETER
                     Set  a  parameter  on the server. By default, libcurl will automatically include a Con-tent-Type: Content-Type:
                     tent-Type: text/parameters header unless a custom one  is  set.  The  interaction  with
                     SET_PARAMTER  is  much  like  a  HTTP  PUT  or POST. An application may either use CUR-LOPT_UPLOAD CURLOPT_UPLOAD
                     LOPT_UPLOAD with CURLOPT_READDATA like a HTTP PUT, or  it  may  use  CURLOPT_POSTFIELDS
                     like  a  HTTP  POST.  No chunked transfers are allowed, so the application must set the
                     CURLOPT_INFILESIZE in the former and CURLOPT_POSTFIELDSIZE in the latter.  Also,  there
                     is no use of multi-part POSTs within RTSP. (Added in 7.20.0)

              CURL_RTSPREQ_RECORD
                     Used to tell the server to record a session. Use the CURLOPT_RANGE option to modify the
                     record time. (Added in 7.20.0)

              CURL_RTSPREQ_RECEIVE
                     This is a special request because it does not send any data to the server. The applica-tion application
                     tion  may  call  this function in order to receive interleaved RTP data. It will return
                     after processing one read buffer of data in order to give the application a  chance  to
                     run. (Added in 7.20.0)

       CURLOPT_RTSP_SESSION_ID
              Pass  a  char * as a parameter to set the value of the current RTSP Session ID for the handle.
              Useful for resuming an in-progress session. Once this value is  set  to  any  non-NULL  value,
              libcurl will return CURLE_RTSP_SESSION_ERROR if ID received from the server does not match. If
              unset (or set to NULL), libcurl will automatically set the ID the first time the  server  sets
              it in a response. (Added in 7.20.0)

       CURLOPT_RTSP_STREAM_URI
              Set  the  stream  URI to operate on by passing a char * . For example, a single session may be
              controlling rtsp://foo/twister/audio and  rtsp://foo/twister/video  and  the  application  can
              switch  to the appropriate stream using this option. If unset, libcurl will default to operat-ing operating
              ing on generic server options by passing '*' in the place of the RTSP Stream URI. This  option
              is  distinct  from  CURLOPT_URL. When working with RTSP, the CURLOPT_STREAM_URI indicates what
              URL to send to the server in the request header while the CURLOPT_URL indicates where to  make
              the   connection  to.   (e.g.  the  CURLOPT_URL  for  the  above  examples  might  be  set  to
              rtsp://foo/twister (Added in 7.20.0)

       CURLOPT_RTSP_TRANSPORT
              Pass a char * to tell libcurl what to pass for the Transport: header for  this  RTSP  session.
              This  is  mainly  a  convenience method to avoid needing to set a custom Transport: header for
              every SETUP request. The application must set a  Transport:  header  before  issuing  a  SETUP
              request. (Added in 7.20.0)

       CURLOPT_RTSP_HEADER
              This option is simply an alias for CURLOPT_HTTP_HEADER. Use this to replace the standard head-ers headers
              ers that RTSP and HTTP share. It is also valid to use the shortcuts such as CURLOPT_USERAGENT.
              (Added in 7.20.0)

       CURLOPT_RTSP_CLIENT_CSEQ
              Manually set the the CSEQ number to issue for the next RTSP request. Useful if the application
              is resuming a previously broken connection. The CSEQ  will  increment  from  this  new  number
              henceforth. (Added in 7.20.0)

       CURLOPT_RTSP_SERVER_CSEQ
              Manually  set  the  CSEQ  number  to  expect for the next RTSP Server->Client request.  At the
              moment, this feature (listening for Server requests) is unimplemented. (Added in 7.20.0)

PROTOCOL OPTIONS
       CURLOPT_TRANSFERTEXT
              A parameter set to 1 tells the library to use ASCII mode for FTP  transfers,  instead  of  the
              default  binary  transfer.  For  win32 systems it does not set the stdout to binary mode. This
              option can be usable when transferring text data between systems with different views on  cer-tain certain
              tain characters, such as newlines or similar.

              libcurl does not do a complete ASCII conversion when doing ASCII transfers over FTP. This is a
              known limitation/flaw that nobody has rectified. libcurl simply sets the  mode  to  ASCII  and
              performs a standard transfer.

       CURLOPT_PROXY_TRANSFER_MODE
              Pass a long. If the value is set to 1 (one), it tells libcurl to set the transfer mode (binary
              or ASCII) for FTP transfers done via a HTTP proxy, by appending ;type=a or ;type=i to the URL.
              Without  this  setting,  or it being set to 0 (zero, the default), CURLOPT_TRANSFERTEXT has no
              effect when doing FTP via a proxy. Beware that not all proxies support this  feature.   (Added
              in 7.18.0)

       CURLOPT_CRLF
              Pass  a  long. If the value is set to 1 (one), libcurl converts Unix newlines to CRLF newlines
              on transfers. Disable this option again by setting the value to 0 (zero).

       CURLOPT_RANGE
              Pass a char * as parameter, which should contain the specified range you want. It should be in
              the format "X-Y", where X or Y may be left out. HTTP transfers also support several intervals,
              separated with commas as in "X-Y,N-M". Using this kind of multiple intervals  will  cause  the
              HTTP  server  to  send  the  response document in pieces (using standard MIME separation tech-niques). techniques).
              niques). For RTSP, the formatting of a range should follow RFC2326 Section  12.29.  For  RTSP,
              byte  ranges are not permitted. Instead, ranges should be given in npt, utc, or smpte formats.

              Pass a NULL to this option to disable the use of ranges.

              Ranges work on HTTP, FTP, FILE (since 7.18.0), and RTSP (since 7.20.0) transfers only.

       CURLOPT_RESUME_FROM
              Pass a long as parameter. It contains the offset in number of bytes that you want the transfer
              to start from. Set this option to 0 to make the transfer start from the beginning (effectively
              disabling resume). For FTP, set this option to -1 to make the transfer start from the  end  of
              the target file (useful to continue an interrupted upload).

              When  doing  uploads  with  FTP, the resume position is where in the local/source file libcurl
              should try to resume the upload from and it will then append the source  file  to  the  remote
              target file.

       CURLOPT_RESUME_FROM_LARGE
              Pass  a  curl_off_t  as parameter. It contains the offset in number of bytes that you want the
              transfer to start from. (Added in 7.11.0)

       CURLOPT_CUSTOMREQUEST
              Pass a pointer to a zero terminated string as parameter. It can be used to specify the request
              instead of GET or HEAD when performing HTTP based requests, instead of LIST and NLST when per-forming performing
              forming FTP directory listings and instead of LIST and RETR when issuing POP3 based  commands.
              This  is particularly useful, for example, for performing a HTTP DELETE request or a POP3 DELE
              command.

              Please don't perform this at will, on HTTP based requests, by making sure your server supports
              the command you are sending first.

              When  you  change  the request method by setting CURLOPT_CUSTOMREQUEST to something, you don't
              actually change how libcurl behaves or acts in regards to the particular  request  method,  it
              will only change the actual string sent in the request.

              For example:

              With  the  HTTP  protocol  when  you tell libcurl to do a HEAD request, but then specify a GET
              though a custom request libcurl will still act as if it sent a HEAD. To  switch  to  a  proper
              HEAD use CURLOPT_NOBODY, to switch to a proper POST use CURLOPT_POST or CURLOPT_POSTFIELDS and
              to switch to a proper GET use CURLOPT_HTTPGET.

              With the POP3 protocol when you tell libcurl to use a custom request it  will  behave  like  a
              LIST or RETR command was sent where it expects data to be returned by the server. As such CUR-LOPT_NOBODY CURLOPT_NOBODY
              LOPT_NOBODY should be used when specifying commands such as DELE and NOOP for example.

              Restore to the internal default by setting this to NULL.

              Many people have wrongly used this option to  replace  the  entire  request  with  their  own,
              including  multiple  headers  and  POST contents. While that might work in many cases, it will
              cause libcurl to send invalid requests and it could possibly confuse the remote server  badly.
              Use CURLOPT_POST and CURLOPT_POSTFIELDS to set POST data. Use CURLOPT_HTTPHEADER to replace or
              extend the set of headers sent by libcurl. Use CURLOPT_HTTP_VERSION to change HTTP version.

              (Support for POP3 added in 7.26.0)

       CURLOPT_FILETIME
              Pass a long. If it is 1, libcurl will attempt to get the modification date of the remote docu-ment document
              ment  in  this  operation. This requires that the remote server sends the time or replies to a
              time querying command. The curl_easy_getinfo(3) function with the  CURLINFO_FILETIME  argument
              can be used after a transfer to extract the received time (if any).

       CURLOPT_NOBODY
              A  parameter  set  to  1 tells the library to not include the body-part in the output. This is
              only relevant for protocols that have separate header and body parts. On HTTP(S) servers, this
              will make libcurl do a HEAD request.

              To  change  request  to  GET, you should use CURLOPT_HTTPGET. Change request to POST with CUR-LOPT_POST CURLOPT_POST
              LOPT_POST etc.

       CURLOPT_INFILESIZE
              When uploading a file to a remote site, this option should be used to tell  libcurl  what  the
              expected  size  of  the  infile  is.  This  value  should  be  passed as a long. See also CUR-LOPT_INFILESIZE_LARGE. CURLOPT_INFILESIZE_LARGE.
              LOPT_INFILESIZE_LARGE.

              For uploading using SCP, this option or CURLOPT_INFILESIZE_LARGE is mandatory.

              When sending emails using SMTP, this command can be used to specify the optional SIZE  parame-ter parameter
              ter for the MAIL FROM command. (Added in 7.23.0)

              This  option  does  not  limit how much data libcurl will actually send, as that is controlled
              entirely by what the read callback returns.

       CURLOPT_INFILESIZE_LARGE
              When uploading a file to a remote site, this option should be used to tell  libcurl  what  the
              expected  size  of  the  infile  is.   This  value should be passed as a curl_off_t. (Added in
              7.11.0)

              For uploading using SCP, this option or CURLOPT_INFILESIZE is mandatory.

              This option does not limit how much data libcurl will actually send,  as  that  is  controlled
              entirely by what the read callback returns.

       CURLOPT_UPLOAD
              A parameter set to 1 tells the library to prepare for an upload. The CURLOPT_READDATA and CUR-LOPT_INFILESIZE CURLOPT_INFILESIZE
              LOPT_INFILESIZE or CURLOPT_INFILESIZE_LARGE options are also interesting for uploads.  If  the
              protocol is HTTP, uploading means using the PUT request unless you tell libcurl otherwise.

              Using  PUT  with HTTP 1.1 implies the use of a "Expect: 100-continue" header.  You can disable
              this header with CURLOPT_HTTPHEADER as usual.

              If you use PUT to a HTTP 1.1 server, you can upload  data  without  knowing  the  size  before
              starting  the  transfer  if  you use chunked encoding. You enable this by adding a header like
              "Transfer-Encoding: chunked" with CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked  trans-fer, transfer,
              fer, you must specify the size.

       CURLOPT_MAXFILESIZE
              Pass  a long as parameter. This allows you to specify the maximum size (in bytes) of a file to
              download. If the file requested is larger than this value, the transfer  will  not  start  and
              CURLE_FILESIZE_EXCEEDED will be returned.

              The  file  size  is  not always known prior to download, and for such files this option has no
              effect even if the file transfer ends up being larger than this  given  limit.  This  concerns
              both FTP and HTTP transfers.

       CURLOPT_MAXFILESIZE_LARGE
              Pass  a  curl_off_t  as parameter. This allows you to specify the maximum size (in bytes) of a
              file to download. If the file requested is larger than this value, the transfer will not start
              and CURLE_FILESIZE_EXCEEDED will be returned. (Added in 7.11.0)

              The  file  size  is  not always known prior to download, and for such files this option has no
              effect even if the file transfer ends up being larger than this  given  limit.  This  concerns
              both FTP and HTTP transfers.

       CURLOPT_TIMECONDITION
              Pass  a  long  as parameter. This defines how the CURLOPT_TIMEVALUE time value is treated. You
              can set this parameter to CURL_TIMECOND_IFMODSINCE or CURL_TIMECOND_IFUNMODSINCE. This feature
              applies to HTTP, FTP, RTSP, and FILE.

              The  last  modification  time of a file is not always known and in such instances this feature
              will have no effect even if the given time condition would not have been  met.  curl_easy_get-info(3) curl_easy_getinfo(3)
              info(3)  with  the  CURLINFO_CONDITION_UNMET option can be used after a transfer to learn if a
              zero-byte successful "transfer" was due to this condition not matching.

       CURLOPT_TIMEVALUE
              Pass a long as parameter. This should be the time in seconds since 1 Jan 1970,  and  the  time
              will be used in a condition as specified with CURLOPT_TIMECONDITION.

CONNECTION OPTIONS
       CURLOPT_TIMEOUT
              Pass  a  long  as  parameter containing the maximum time in seconds that you allow the libcurl
              transfer operation to take. Normally, name lookups can take a considerable time  and  limiting
              operations  to  less than a few minutes risk aborting perfectly normal operations. This option
              will cause curl to use the SIGALRM to enable time-outing system calls.

              In unix-like systems, this might cause signals to be used unless CURLOPT_NOSIGNAL is set.

              Default timeout is 0 (zero) which means it never times out.

       CURLOPT_TIMEOUT_MS
              Like CURLOPT_TIMEOUT but takes number of milliseconds instead. If libcurl is built to use  the
              standard system name resolver, that portion of the transfer will still use full-second resolu-tion resolution
              tion for timeouts with a minimum timeout allowed of one second.  (Added in 7.16.2)

       CURLOPT_LOW_SPEED_LIMIT
              Pass a long as parameter. It contains the transfer speed in bytes per second that the transfer
              should  be below during CURLOPT_LOW_SPEED_TIME seconds for the library to consider it too slow
              and abort.

       CURLOPT_LOW_SPEED_TIME
              Pass a long as parameter. It contains the time in seconds that the transfer  should  be  below
              the CURLOPT_LOW_SPEED_LIMIT for the library to consider it too slow and abort.

       CURLOPT_MAX_SEND_SPEED_LARGE
              Pass a curl_off_t as parameter.  If an upload exceeds this speed (counted in bytes per second)
              on cumulative average during the transfer, the transfer will pause to keep  the  average  rate
              less than or equal to the parameter value.  Defaults to unlimited speed. (Added in 7.15.5)

       CURLOPT_MAX_RECV_SPEED_LARGE
              Pass  a  curl_off_t as parameter.  If a download exceeds this speed (counted in bytes per sec-ond) second)
              ond) on cumulative average during the transfer, the transfer will pause to  keep  the  average
              rate less than or equal to the parameter value. Defaults to unlimited speed. (Added in 7.15.5)

       CURLOPT_MAXCONNECTS
              Pass a long. The set number will be the persistent connection cache size. The set amount  will
              be  the  maximum amount of simultaneously open connections that libcurl may cache in this easy
              handle. Default is 5, and there isn't much point in changing this value unless  you  are  per-fectly perfectly
              fectly  aware  of  how  this  works and changes libcurl's behaviour. This concerns connections
              using any of the protocols that support persistent connections.

              When reaching the maximum limit, curl closes the oldest one in the cache to prevent increasing
              the number of open connections.

              If  you  already have performed transfers with this curl handle, setting a smaller MAXCONNECTS
              than before may cause open connections to get closed unnecessarily.

              If you add this easy handle to a multi handle, this setting is not acknowledged, and you  must
              instead use curl_multi_setopt(3) and the CURLMOPT_MAXCONNECTS option.

       CURLOPT_CLOSEPOLICY
              (Obsolete) This option does nothing.

       CURLOPT_FRESH_CONNECT
              Pass  a long. Set to 1 to make the next transfer use a new (fresh) connection by force. If the
              connection cache is full before this connection, one  of  the  existing  connections  will  be
              closed as according to the selected or default policy. This option should be used with caution
              and only if you understand what it does. Set this to 0 to have  libcurl  attempt  re-using  an
              existing connection (default behavior).

       CURLOPT_FORBID_REUSE
              Pass  a  long.  Set  to 1 to make the next transfer explicitly close the connection when done.
              Normally, libcurl keeps all connections alive when done with one transfer in case a succeeding
              one  follows  that  can  re-use them.  This option should be used with caution and only if you
              understand what it does. Set to 0 to have libcurl keep the connection open for possible  later
              re-use (default behavior).

       CURLOPT_CONNECTTIMEOUT
              Pass  a  long.  It should contain the maximum time in seconds that you allow the connection to
              the server to take.  This only limits the connection phase, once it has connected, this option
              is of no more use. Set to zero to switch to the default built-in connection timeout - 300 sec-onds. seconds.
              onds. See also the CURLOPT_TIMEOUT option.

              In unix-like systems, this might cause signals to be used unless CURLOPT_NOSIGNAL is set.

       CURLOPT_CONNECTTIMEOUT_MS
              Like CURLOPT_CONNECTTIMEOUT but takes the number of milliseconds instead. If libcurl is  built
              to use the standard system name resolver, that portion of the connect will still use full-sec-ond full-second
              ond resolution for timeouts with a minimum timeout allowed of one second.  (Added in 7.16.2)

       CURLOPT_IPRESOLVE
              Allows an application to select what kind of IP addresses to use when  resolving  host  names.
              This is only interesting when using host names that resolve addresses using more than one ver-sion version
              sion of IP. The allowed values are:

              CURL_IPRESOLVE_WHATEVER
                     Default, resolves addresses to all IP versions that your system allows.

              CURL_IPRESOLVE_V4
                     Resolve to IPv4 addresses.

              CURL_IPRESOLVE_V6
                     Resolve to IPv6 addresses.

       CURLOPT_CONNECT_ONLY
              Pass a long. If the parameter equals 1, it tells the library to perform all the required proxy
              authentication  and  connection  setup,  but no data transfer.  This option is implemented for
              HTTP, SMTP and POP3.

              The option can be used to simply test a connection to a server, but is more useful  when  used
              with the CURLINFO_LASTSOCKET option to curl_easy_getinfo(3) as the library can set up the con-nection connection
              nection and then the application can obtain the most recently used  socket  for  special  data
              transfers. (Added in 7.15.2)

       CURLOPT_USE_SSL
              Pass  a long using one of the values from below, to make libcurl use your desired level of SSL
              for the transfer. (Added in 7.11.0)

              This is for enabling SSL/TLS when you use FTP, SMTP, POP3, IMAP etc.

              (This option was known as CURLOPT_FTP_SSL up to  7.16.4,  and  the  constants  were  known  as
              CURLFTPSSL_*)

              CURLUSESSL_NONE
                     Don't attempt to use SSL.

              CURLUSESSL_TRY
                     Try using SSL, proceed as normal otherwise.

              CURLUSESSL_CONTROL
                     Require SSL for the control connection or fail with CURLE_USE_SSL_FAILED.

              CURLUSESSL_ALL
                     Require SSL for all communication or fail with CURLE_USE_SSL_FAILED.

       CURLOPT_RESOLVE
              Pass  a  pointer  to  a  linked  list of strings with host name resolve information to use for
              requests with this handle. The linked list should be a fully valid list of  struct  curl_slist
              structs   properly   filled   in.   Use   curl_slist_append(3)   to   create   the   list  and
              curl_slist_free_all(3) to clean up an entire list.

              Each single name resolve string should be written using  the  format  HOST:PORT:ADDRESS  where
              HOST  is  the  name  libcurl will try to resolve, PORT is the port number of the service where
              libcurl wants to connect to the HOST and ADDRESS is the numerical IP address.  If  libcurl  is
              built to support IPv6, ADDRESS can of course be either IPv4 or IPv6 style addressing.

              This  option  effectively  pre-populates  the DNS cache with entries for the host+port pair so
              redirects and everything that operations against the HOST+PORT will instead use your  provided
              ADDRESS.

              You  can  remove  names  from  the  DNS cache again, to stop providing these fake resolves, by
              including a string in the linked list that uses the format "-HOST:PORT". The host name must be
              prefixed  with  a  dash, and the host name and port number must exactly match what was already
              added previously.

              (Added in 7.21.3)

       CURLOPT_DNS_SERVERS
              Set the list of DNS servers to be used instead of the system default.  The format of  the  dns
              servers option is:

              host[:port][,host[:port]]...

              For example:

              192.168.1.100,192.168.1.101,3.4.5.6

              This  option requires that libcurl was built with a resolver backend that supports this opera-tion. operation.
              tion. The c-ares backend is the only such one.

              (Added in 7.24.0)

       CURLOPT_ACCEPTTIMEOUT_MS
              Pass a long telling libcurl the maximum number of milliseconds to wait for a server to connect
              back  to  libcurl  when  an  active FTP connection is used. If no timeout is set, the internal
              default of 60000 will be used. (Added in 7.24.0)

SSL and SECURITY OPTIONS
       CURLOPT_SSLCERT
              Pass a pointer to a zero terminated string as parameter. The string should be the file name of
              your certificate. The default format is "PEM" and can be changed with CURLOPT_SSLCERTTYPE.

              With  NSS  this  can also be the nickname of the certificate you wish to authenticate with. If
              you want to use a file from the current directory, please precede  it  with  "./"  prefix,  in
              order to avoid confusion with a nickname.

       CURLOPT_SSLCERTTYPE
              Pass  a  pointer  to a zero terminated string as parameter. The string should be the format of
              your certificate. Supported formats are "PEM" and "DER".  (Added in 7.9.3)

       CURLOPT_SSLKEY
              Pass a pointer to a zero terminated string as parameter. The string should be the file name of
              your private key. The default format is "PEM" and can be changed with CURLOPT_SSLKEYTYPE.

       CURLOPT_SSLKEYTYPE
              Pass  a  pointer  to a zero terminated string as parameter. The string should be the format of
              your private key. Supported formats are "PEM", "DER" and "ENG".

              The format "ENG" enables you to load the private key from a crypto engine. In this  case  CUR-LOPT_SSLKEY CURLOPT_SSLKEY
              LOPT_SSLKEY  is  used as an identifier passed to the engine. You have to set the crypto engine
              with CURLOPT_SSLENGINE.  "DER" format key file currently does not work because  of  a  bug  in
              OpenSSL.

       CURLOPT_KEYPASSWD
              Pass  a  pointer  to  a  zero  terminated string as parameter. It will be used as the password
              required to use the CURLOPT_SSLKEY or  CURLOPT_SSH_PRIVATE_KEYFILE  private  key.   You  never
              needed a pass phrase to load a certificate but you need one to load your private key.

              (This  option  was  known as CURLOPT_SSLKEYPASSWD up to 7.16.4 and CURLOPT_SSLCERTPASSWD up to
              7.9.2)

       CURLOPT_SSLENGINE
              Pass a pointer to a zero terminated string as parameter. It will be used as the identifier for
              the crypto engine you want to use for your private key.

              If the crypto device cannot be loaded, CURLE_SSL_ENGINE_NOTFOUND is returned.

       CURLOPT_SSLENGINE_DEFAULT
              Sets the actual crypto engine as the default for (asymmetric) crypto operations.

              If the crypto device cannot be set, CURLE_SSL_ENGINE_SETFAILED is returned.

              Even  though  this  option doesn't need any parameter, in some configurations curl_easy_setopt
              might be defined as a macro taking exactly three arguments.  Therefore,  it's  recommended  to
              pass 1 as parameter to this option.

       CURLOPT_SSLVERSION
              Pass  a long as parameter to control what version of SSL/TLS to attempt to use.  The available
              options are:

              CURL_SSLVERSION_DEFAULT
                     The default action. This will attempt to figure out the remote  SSL  protocol  version,
                     i.e.  either  SSLv3  or  TLSv1  (but  not  SSLv2, which became disabled by default with
                     7.18.1).

              CURL_SSLVERSION_TLSv1
                     Force TLSv1

              CURL_SSLVERSION_SSLv2
                     Force SSLv2

              CURL_SSLVERSION_SSLv3
                     Force SSLv3

       CURLOPT_SSL_VERIFYPEER
              Pass a long as parameter. By default, curl assumes a value of 1.

              This option determines whether curl verifies the authenticity of  the  peer's  certificate.  A
              value of 1 means curl verifies; 0 (zero) means it doesn't.

              When  negotiating  a  SSL  connection, the server sends a certificate indicating its identity.
              Curl verifies whether the certificate is authentic, i.e. that you can trust that the server is
              who  the certificate says it is.  This trust is based on a chain of digital signatures, rooted
              in certification authority (CA) certificates you supply.  curl uses a  default  bundle  of  CA
              certificates  (the  path  for  that is determined at build time) and you can specify alternate
              certificates with the CURLOPT_CAINFO option or the CURLOPT_CAPATH option.

              When CURLOPT_SSL_VERIFYPEER is nonzero, and the verification fails to prove that the  certifi-cate certificate
              cate  is authentic, the connection fails.  When the option is zero, the peer certificate veri-fication verification
              fication succeeds regardless.

              Authenticating the certificate is not by itself very useful.  You  typically  want  to  ensure
              that  the server, as authentically identified by its certificate, is the server you mean to be
              talking to.  Use CURLOPT_SSL_VERIFYHOST to control that. The check that the host name  in  the
              certificate  is valid for the host name you're connecting to is done independently of the CUR-LOPT_SSL_VERIFYPEER CURLOPT_SSL_VERIFYPEER
              LOPT_SSL_VERIFYPEER option.

       CURLOPT_CAINFO
              Pass a char * to a zero terminated string naming a file holding one or  more  certificates  to
              verify  the  peer  with.   This  makes  sense  only  when  used  in  combination with the CUR-LOPT_SSL_VERIFYPEER CURLOPT_SSL_VERIFYPEER
              LOPT_SSL_VERIFYPEER option.  If CURLOPT_SSL_VERIFYPEER is zero, CURLOPT_CAINFO need  not  even
              indicate an accessible file.

              This  option  is by default set to the system path where libcurl's cacert bundle is assumed to
              be stored, as established at build time.

              If curl is built against the NSS SSL library, the NSS PEM PKCS#11 module (libnsspem.so)  needs
              to be available for this option to work properly.

       CURLOPT_ISSUERCERT
              Pass  a  char * to a zero terminated string naming a file holding a CA certificate in PEM for-mat. format.
              mat. If the option is set, an additional check against the peer certificate  is  performed  to
              verify  the  issuer  is indeed the one associated with the certificate provided by the option.
              This additional check is useful in multi-level PKI where one needs to enforce  that  the  peer
              certificate is from a specific branch of the tree.

              This  option makes sense only when used in combination with the CURLOPT_SSL_VERIFYPEER option.
              Otherwise, the result of the check is not considered as failure.

              A specific error code (CURLE_SSL_ISSUER_ERROR) is defined with the option, which  is  returned
              if  the setup of the SSL/TLS session has failed due to a mismatch with the issuer of peer cer-tificate certificate
              tificate (CURLOPT_SSL_VERIFYPEER has to be set too for the check to fail). (Added in 7.19.0)

       CURLOPT_CAPATH
              Pass a char * to a zero terminated string naming a directory holding multiple CA  certificates
              to  verify  the peer with. If libcurl is built against OpenSSL, the certificate directory must
              be prepared using the openssl c_rehash utility.  This makes sense only when used  in  combina-tion combination
              tion  with the CURLOPT_SSL_VERIFYPEER option.  If CURLOPT_SSL_VERIFYPEER is zero, CURLOPT_CAP-ATH CURLOPT_CAPATH
              ATH need not even indicate an accessible path.  The CURLOPT_CAPATH  function  apparently  does
              not  work  in  Windows  due to some limitation in openssl. This option is OpenSSL-specific and
              does nothing if libcurl is built to use GnuTLS. NSS-powered libcurl provides the  option  only
              for backward compatibility.

       CURLOPT_CRLFILE
              Pass  a char * to a zero terminated string naming a file with the concatenation of CRL (in PEM
              format) to use in the certificate validation that occurs during the SSL exchange.

              When curl is built to use NSS or GnuTLS, there is no way to influence the use of CRL passed to
              help   in   the   verification   process.   When   libcurl  is  built  with  OpenSSL  support,
              X509_V_FLAG_CRL_CHECK and X509_V_FLAG_CRL_CHECK_ALL are both set, requiring CRL check  against
              all the elements of the certificate chain if a CRL file is passed.

              This  option makes sense only when used in combination with the CURLOPT_SSL_VERIFYPEER option.

              A specific error code (CURLE_SSL_CRL_BADFILE) is defined with the option. It is returned  when
              the  SSL exchange fails because the CRL file cannot be loaded.  A failure in certificate veri-fication verification
              fication due to a revocation information found in the  CRL  does  not  trigger  this  specific
              error. (Added in 7.19.0)

       CURLOPT_SSL_VERIFYHOST
              Pass a long as parameter.

              This  option  determines whether libcurl verifies that the server cert is for the server it is
              known as.

              When negotiating a SSL connection, the server sends a certificate indicating its identity.

              When CURLOPT_SSL_VERIFYHOST is 2, that certificate must indicate that the server is the server
              to which you meant to connect, or the connection fails.

              Curl  considers  the server the intended one when the Common Name field or a Subject Alternate
              Name field in the certificate matches the host name in the URL to which you told Curl to  con-nect. connect.
              nect.

              When  the value is 1, libcurl will return a failure. It was previously (in 7.28.0 and earlier)
              a debug option of some sorts, but it is no longer supported due to frequently leading to  pro-grammer programmer
              grammer mistakes.

              When the value is 0, the connection succeeds regardless of the names in the certificate.

              The default value for this option is 2.

              This  option  controls checking the server's certificate's claimed identity.  The server could
              be lying.  To control lying, see CURLOPT_SSL_VERIFYPEER.  If libcurl is built against NSS  and
              CURLOPT_SSL_VERIFYPEER is zero, CURLOPT_SSL_VERIFYHOST is ignored.


       CURLOPT_CERTINFO
              Pass  a  long set to 1 to enable libcurl's certificate chain info gatherer. With this enabled,
              libcurl (if built with OpenSSL) will extract lots of information and data about  the  certifi-cates certificates
              cates  in  the  certificate  chain  used  in the SSL connection. This data is then possible to
              extract after a transfer using curl_easy_getinfo(3) and its option  CURLINFO_CERTINFO.  (Added
              in 7.19.1)

       CURLOPT_RANDOM_FILE
              Pass  a  char * to a zero terminated file name. The file will be used to read from to seed the
              random engine for SSL. The more random the specified file is, the more secure the SSL  connec-tion connection
              tion will become.

       CURLOPT_EGDSOCKET
              Pass a char * to the zero terminated path name to the Entropy Gathering Daemon socket. It will
              be used to seed the random engine for SSL.

       CURLOPT_SSL_CIPHER_LIST
              Pass a char *, pointing to a zero terminated string holding the list of ciphers to use for the
              SSL  connection.  The  list  must  be syntactically correct, it consists of one or more cipher
              strings separated by colons. Commas or spaces are also acceptable separators  but  colons  are
              normally used, !, - and + can be used as operators.

              For  OpenSSL  and GnuTLS valid examples of cipher lists include 'RC4-SHA', 'SHA1+DES', 'TLSv1'
              and 'DEFAULT'. The default list is normally set when you compile OpenSSL.

              You'll     find     more     details     about     cipher     lists     on      this      URL:
              http://www.openssl.org/docs/apps/ciphers.html

              For  NSS,  valid  examples  of cipher lists include 'rsa_rc4_128_md5', 'rsa_aes_128_sha', etc.
              With NSS you don't add/remove ciphers. If one uses this option then all known ciphers are dis-abled disabled
              abled and only those passed in are enabled.

              You'll  find  more  details  about  the  NSS  cipher  lists  on  this  URL: http://git.fedora-
              hosted.org/cgit/mod_nss.git/plain/docs/mod_nss.html#Directives


       CURLOPT_SSL_SESSIONID_CACHE
              Pass a long set to 0 to disable libcurl's use of SSL session-ID caching.  Set  this  to  1  to
              enable  it.  By  default all transfers are done using the cache. While nothing ever should get
              hurt by attempting to reuse SSL session-IDs, there seem to be broken  SSL  implementations  in
              the wild that may require you to disable this in order for you to succeed. (Added in 7.16.0)

       CURLOPT_SSL_OPTIONS
              Pass a long with a bitmask to tell libcurl about specific SSL behaviors.

              CURLSSLOPT_ALLOW_BEAST  is  the  only  supported  bit  and  by setting this the user will tell
              libcurl to not attempt to use any workarounds for a security flaw in the SSL3 and TLS1.0  pro-tocols. protocols.
              tocols.  If this option isn't used or this bit is set to 0, the SSL layer libcurl uses may use
              a work-around for this flaw although  it  might  cause  interoperability  problems  with  some
              (older)  SSL  implementations. WARNING: avoiding this work-around loosens the security, and by
              setting this option to 1 you ask for exactly that. (Added in 7.25.0)

       CURLOPT_KRBLEVEL
              Pass a char * as parameter. Set the kerberos security level for FTP; this  also  enables  ker-beros kerberos
              beros  awareness.   This  is  a  string, 'clear', 'safe', 'confidential' or 'private'.  If the
              string is set but doesn't match one of these, 'private' will be used. Set the string  to  NULL
              to disable kerberos support for FTP.

              (This option was known as CURLOPT_KRB4LEVEL up to 7.16.3)

       CURLOPT_GSSAPI_DELEGATION
              Set the parameter to CURLGSSAPI_DELEGATION_FLAG to allow unconditional GSSAPI credential dele-gation. delegation.
              gation.  The delegation is disabled by default since 7.21.7.  Set the  parameter  to  CURLGSS-API_DELEGATION_POLICY_FLAG CURLGSSAPI_DELEGATION_POLICY_FLAG
              API_DELEGATION_POLICY_FLAG  to  delegate only if the OK-AS-DELEGATE flag is set in the service
              ticket in case this feature is supported by the GSSAPI implementation and  the  definition  of
              GSS_C_DELEG_POLICY_FLAG was available at compile-time.  (Added in 7.22.0)

SSH OPTIONS
       CURLOPT_SSH_AUTH_TYPES
              Pass  a  long  set  to  a  bitmask  consisting  of  one  or  more  of  CURLSSH_AUTH_PUBLICKEY,
              CURLSSH_AUTH_PASSWORD, CURLSSH_AUTH_HOST, CURLSSH_AUTH_KEYBOARD  and  CURLSSH_AUTH_AGENT.  Set
              CURLSSH_AUTH_ANY  to  let  libcurl  pick  a  suitable  one. Currently CURLSSH_AUTH_HOST has no
              effect. (Added in 7.16.1) If CURLSSH_AUTH_AGENT is used, libcurl attempts to connect  to  ssh-agent sshagent
              agent or pageant and let the agent attempt the authentication. (Added in 7.28.0)

       CURLOPT_SSH_HOST_PUBLIC_KEY_MD5
              Pass  a char * pointing to a string containing 32 hexadecimal digits. The string should be the
              128 bit MD5 checksum of the remote host's public key, and libcurl will reject  the  connection
              to  the  host unless the md5sums match. This option is only for SCP and SFTP transfers. (Added
              in 7.17.1)

       CURLOPT_SSH_PUBLIC_KEYFILE
              Pass a char * pointing to a file name for your public key. If not used,  libcurl  defaults  to
              $HOME/.ssh/id_dsa.pub  if  the  HOME environment variable is set, and just "id_dsa.pub" in the
              current directory if HOME is not set.  (Added in 7.16.1) If an empty string is passed, libcurl
              will  pass  no public key to libssh2 which then tries to compute it from the private key, this
              is known to work when libssh2 1.4.0+ is linked against OpenSSL. (Added in 7.26.0)

       CURLOPT_SSH_PRIVATE_KEYFILE
              Pass a char * pointing to a file name for your private key. If not used, libcurl  defaults  to
              $HOME/.ssh/id_dsa  if  the  HOME environment variable is set, and just "id_dsa" in the current
              directory if HOME is not set.  If the file is password-protected, set the password  with  CUR-LOPT_KEYPASSWD. CURLOPT_KEYPASSWD.
              LOPT_KEYPASSWD. (Added in 7.16.1)

       CURLOPT_SSH_KNOWNHOSTS
              Pass  a  pointer  to  a zero terminated string holding the file name of the known_host file to
              use.  The known_hosts file should use the OpenSSH file format as supported by libssh2. If this
              file  is specified, libcurl will only accept connections with hosts that are known and present
              in that file, with a matching public key. Use CURLOPT_SSH_KEYFUNCTION  to  alter  the  default
              behavior on host and key (mis)matching. (Added in 7.19.6)

       CURLOPT_SSH_KEYFUNCTION
              Pass  a pointer to a curl_sshkeycallback function. It gets called when the known_host matching
              has been done, to allow the application to act and decide for  libcurl  how  to  proceed.  The
              callback will only be called if CURLOPT_SSH_KNOWNHOSTS is also set.

              The  curl_sshkeycallback  function  gets  passed the CURL handle, the key from the known_hosts
              file, the key from the remote site, info from libcurl on the  matching  status  and  a  custom
              pointer  (set  with  CURLOPT_SSH_KEYDATA). It MUST return one of the following return codes to
              tell libcurl how to act:

              CURLKHSTAT_FINE_ADD_TO_FILE
                     The host+key is accepted and libcurl will append it to the known_hosts file before con-tinuing continuing
                     tinuing  with  the  connection. This will also add the host+key combo to the known_host
                     pool kept in memory if it wasn't already present there. The adding of data to the  file
                     is  done  by  completely  replacing the file with a new copy, so the permissions of the
                     file must allow this.

              CURLKHSTAT_FINE
                     The host+key is accepted libcurl will continue with the connection. This will also  add
                     the  host+key  combo to the known_host pool kept in memory if it wasn't already present
                     there.

              CURLKHSTAT_REJECT
                     The host+key is rejected. libcurl will deny the connection to continue and it  will  be
                     closed.

              CURLKHSTAT_DEFER
                     The  host+key is rejected, but the SSH connection is asked to be kept alive.  This fea-ture feature
                     ture could be used when the app wants to somehow return back and act  on  the  host+key
                     situation  and  then  retry  without needing the overhead of setting it up from scratch
                     again.
        (Added in 7.19.6)

       CURLOPT_SSH_KEYDATA
              Pass a void * as parameter. This pointer will be passed along verbatim  to  the  callback  set
              with CURLOPT_SSH_KEYFUNCTION. (Added in 7.19.6)

OTHER OPTIONS
       CURLOPT_PRIVATE
              Pass  a void * as parameter, pointing to data that should be associated with this curl handle.
              The pointer can subsequently be retrieved using curl_easy_getinfo(3) with the CURLINFO_PRIVATE
              option. libcurl itself does nothing with this data. (Added in 7.10.3)

       CURLOPT_SHARE
              Pass a share handle as a parameter. The share handle must have been created by a previous call
              to curl_share_init(3). Setting this option, will make this curl handle use the data  from  the
              shared  handle  instead  of  keeping  the data to itself. This enables several curl handles to
              share data. If the curl handles are used simultaneously in multiple threads, you MUST use  the
              locking methods in the share handle. See curl_share_setopt(3) for details.

              If  you  add a share that is set to share cookies, your easy handle will use that cookie cache
              and get the cookie engine enabled. If you unshare an object that was using cookies (or  change
              to another object that doesn't share cookies), the easy handle will get its cookie engine dis-abled. disabled.
              abled.

              Data that the share object is not set to share will be dealt with the  usual  way,  as  if  no
              share was used.

       CURLOPT_NEW_FILE_PERMS
              Pass  a  long as a parameter, containing the value of the permissions that will be assigned to
              newly created files on the remote server.  The default value is _644, but any valid value  can
              be  used.   The  only  protocols that can use this are sftp://, scp://, and file://. (Added in
              7.16.4)

       CURLOPT_NEW_DIRECTORY_PERMS
              Pass a long as a parameter, containing the value of the permissions that will be  assigned  to
              newly  created  directories  on  the  remote server.  The default value is _755, but any valid
              value can be used.  The only protocols that can use this are  sftp://,  scp://,  and  file://.
              (Added in 7.16.4)

TELNET OPTIONS
       CURLOPT_TELNETOPTIONS
              Provide a pointer to a curl_slist with variables to pass to the telnet negotiations. The vari-ables variables
              ables should be in the format <option=value>. libcurl supports the options 'TTYPE', 'XDISPLOC'
              and 'NEW_ENV'. See the TELNET standard for details.

RETURN VALUE
       CURLE_OK  (zero)  means  that  the  option  was  set  properly,  non-zero  means an error occurred as
       <curl/curl.h> defines. See the libcurl-errors(3) man page for the full list with descriptions.

       If you try to set an option that libcurl doesn't know about, perhaps because the library is  too  old
       to  support  it  or  the  option  was  removed  in  a  recent  version,  this  function  will  return
       CURLE_FAILED_INIT.

SEE ALSO
       curl_easy_init(3), curl_easy_cleanup(3), curl_easy_reset(3)



libcurl 7.20.0                                   1 Jan 2010                              curl_easy_setopt(3)

Reporting Problems

The way to report a problem with this manual page depends on the type of problem:

Content errors
Report errors in the content of this documentation with the feedback links below.
Bug reports
Report bugs in the functionality of the described tool or API through Bug Reporter.
Formatting problems
Report formatting mistakes in the online version of these pages with the feedback links below.

Feedback