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Important: The information in this document is obsolete and should not be used for new development.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
Low-Level HFS Routines / Opening Files


PBHOpenRF

You can use the PBHOpenRF function to open the resource fork of file.

FUNCTION PBHOpenRF (paramBlock: HParmBlkPtr; async: Boolean): 
                     OSErr;
paramBlock
A pointer to a basic HFS parameter block.
async
A Boolean value that specifies asynchronous (TRUE) or synchronous (FALSE) execution.
-->ioCompletionProcPtrA pointer to a completion routine.
<--ioResultOSErrThe result code of the function.
-->ioNamePtrStringPtrA pointer to a pathname.
-->ioVRefNumIntegerA volume specification.
<--ioRefNumIntegerA file reference number.
-->ioPermssnSignedByteThe read/write permission.
-->ioDirIDLongIntA directory ID.

DESCRIPTION
The PBHOpenRF function creates an access path to the resource fork of a file and returns a file reference number in the ioRefNum field.

SPECIAL CONSIDERATIONS
Generally your application should use Resource Manager routines rather than File Manager routines to access a file's resource fork. The PBHOpenRF 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 for PBHOpenRF is _HOpenRF.

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