Important: The information in this document is obsolete and should not be used for new development.
HOpenResFile
If theFSpOpenResFile
function is not available, you can useHOpenResFile
to open a file's resource fork.
FUNCTION HOpenResFile (vRefNum: Integer; dirID: LongInt; fileName: Str255; permission: SignedByte): Integer;
vRefNum
- The volume reference number of the volume on which the file is located.
dirID
- The directory ID of the directory where the file is located.
fileName
- The name of the file whose resource fork is to be opened.
permission
- A constant for one of the read/write permission combinations.
DESCRIPTION
TheHOpenResFile
function opens the resource fork of the file with the name specified by thefileName
parameter in the directory specified by thevRefNum
anddirID
parameters. It also makes this file the current resource file.You can specify the access path permission for the resource fork by setting the
permission
parameter to one of these constants:
CONST fsCurPerm = 0; {whatever is currently allowed} fsRdPerm = 1; {read-only permission} fsWrPerm = 2; {write permission} fsRdWrPerm = 3; {exclusive read/write permission} fsRdWrShPerm = 4; {shared read/write permission}See page 1-55 for information about specifying access path permission withFSpOpenResFile
. The same information applies toHOpenResFile
.The Resource Manager reads the resource map from the resource fork of the specified file into memory. It also reads into memory every resource whose
resPreload
attribute is set.The
HOpenResFile
function returns a file reference number for the file. You can use this file reference number to refer to the file in other Resource Manager routines. If the file's resource fork is already open,HOpenResFile
returns the file reference number but does not make that file the current resource file.If the
HOpenResFile
function fails to open the specified file's resource fork (because there's no file with the specified name or because there are permission problems), it returns -1 as the file reference number. Use theResError
function to determine what kind of error occurred.You don't have to call
HOpenResFile
to open the System file's resource fork or an application file's resource fork. These files are opened automatically when the system and the application start up, respectively. To get the file reference number for your application, call theCurResFile
function after the application starts up and before you open the resource forks for any other files.The
HOpenResFile
function checks that the information in the resource map is internally consistent. If it isn't,ResError
returns the result codemapReadErr
.To open a resource fork just for block-level operations, such as copying files without reading the resource map into memory, use the File Manager function
OpenRF
.SPECIAL CONSIDERATIONS
TheHOpenResFile
function may move or purge memory blocks in the application heap. Your application should not call this function at interrupt time.It's possible to create multiple, unique, read-only access paths to a resource fork using
HOpenResFile
; however, you should avoid doing so. See page 1-56 for discussion of this issue in relation toFSpOpenResFile
. TheHOpenResFile
function works the same way.Versions of system software before System 7 do not allow you to use
HOpenResFile
to open a second access path, with write access, to a resource fork. In this case,HOpenResFile
returns the reference number already assigned to the file.If you want to open the resource fork for another application (or any resource fork other than your application's that includes
'CODE'
resources), you must bracket your calls toHOpenResFile
with calls toSetResLoad
with theload
parameter set toFALSE
and then toTRUE
. You must also avoid making intersegment calls while the other application's resource fork is open. The discussion of this issue in relation toFSpOpenResFile
(page 1-56) also applies toHOpenResFile
.ASSEMBLY-LANGUAGE INFORMATION
A handle to the resource map for the most recently opened resource fork is stored in the global variableTopMapHndl
.RESULT CODES
noErr 0 No error nsvErr -35 No such volume ioErr -36 I/O error bdNamErr -37 Bad filename or volume name (perhaps zero length) eofErr -39 End of file tmfoErr -42 Too many files open fnfErr -43 File not found opWrErr -49 File already open with write permission permErr -54 Attempt to open locked file for writing extFSErr -58 Volume belongs to an external file system memFullErr -108 Not enough room in heap zone dirNFErr -120 Directory not found mapReadErr -199 Map inconsistent with operation SEE ALSO
To check for errors, call theResError
function as described on page 1-47.For more information about
permission
parameter constants and theOpenRF
function, see Inside Macintosh: Files.