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Important: The information in this document is obsolete and should not be used for new development.

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Inside Macintosh: Files /
Chapter 2 - File Manager / File Manager Reference
File System Specification Routines / Opening Files


FSpOpenRF

You can use the FSpOpenRF function to open a file's resource fork.

FUNCTION FSpOpenRF (spec: FSSpec; permission: SignedByte;
                     VAR refNum: Integer): OSErr;
spec
An FSSpec record specifying the file whose resource fork is to be opened.
permission
A constant indicating the desired file access permissions.
refNum
A reference number of an access path to the file's resource fork.
DESCRIPTION
The FSpOpenRF function creates an access path to the resource fork of a file and returns, in the refNum parameter, an access path reference number to that fork. You can pass that reference number as a parameter to any of the low- or high-level file access routines.
The permission parameter should contain a constant indicating the desired file
access permissions.

SPECIAL CONSIDERATIONS
Generally, your application should use Resource Manager routines rather than File Manager routines to access a file's resource fork. The FSpOpenRF function does not read the resource map into memory and is generally useful only for applications (such as utilities that copy files) that need block-level access to a resource fork. In particular, you should not use the resource fork of a file to hold nonresource data. Many parts of the system software assume that a resource fork always contains resource data.

ASSEMBLY-LANGUAGE INFORMATION
The trap macro and routine selector for FSpOpenRF are
Trap macroSelector
_HighLevelHFSDispatch$0003

RESULT CODES
noErr0No error
nsvErr-35No such volume
ioErr-36I/O error
bdNamErr-37Bad filename
tmfoErr-42Too many files open
fnfErr-43File not found
opWrErr-49File already open for writing
permErr-54Attempt to open locked file for writing
dirNFErr-120Directory not found or incomplete pathname
afpAccessDenied-5000User does not have the correct access to the file

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© Apple Computer, Inc.
2 JUL 1996