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GETSERVENT(3)            BSD Library Functions Manual            GETSERVENT(3)

     getservent, getservbyport, getservbyname, setservent, endservent -- get service entry

     Standard C Library (libc, -lc)

     #include <netdb.h>

     struct servent *

     struct servent *
     getservbyname(const char *name, const char *proto);

     struct servent *
     getservbyport(int port, const char *proto);

     setservent(int stayopen);


     The getservent(), getservbyname(), and getservbyport() functions each return a pointer to an object
     with the following structure containing the broken-out fields of a line in the network services data
     base, /etc/services.

           struct  servent {
                   char    *s_name;        /* official name of service */
                   char    **s_aliases;    /* alias list */
                   int     s_port;         /* port service resides at */
                   char    *s_proto;       /* protocol to use */

     The members of this structure are:

     s_name     The official name of the service.

     s_aliases  A zero terminated list of alternate names for the service.

     s_port     The port number at which the service resides.  Port numbers are returned in network byte

     s_proto    The name of the protocol to use when contacting the service.

     The getservent() function reads the next line of the file, opening the file if necessary.

     The setservent() function opens and rewinds the file.  If the stayopen flag is non-zero, the net data
     base will not be closed after each call to getservbyname() or getservbyport().

     The endservent() function closes the file.

     The getservbyname() and getservbyport() functions sequentially search from the beginning of the file
     until a matching protocol name or port number (which must be specified in network byte order) is found,
     or until EOF is encountered.  If a protocol name is also supplied (non- NULL), searches must also match
     the protocol.


     Null pointer (0) returned on EOF or error.

     getprotoent(3), services(5)

     The getservent(), getservbyport(), getservbyname(), setservent(), and endservent() functions appeared
     in 4.2BSD.

     These functions use a thread-specific data storage; if the data is needed for future use, it should be
     copied before any subsequent calls overwrite it.  Expecting port numbers to fit in a 32 bit quantity is
     probably naive.

BSD                              July 9, 1995                              BSD

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