Opens the resource fork of file.

OSErr PBHOpenRFAsync (
    HParmBlkPtr paramBlock
);

paramBlock

A pointer to a basic HFS parameter block.

function result

A result code.

DISCUSSION

The relevant fields of the parameter block are:

• ioCompletion

  On input, a pointer to a completion function.

• ioResult

  On output, the result code of the function.

• ioNamePtr

  On input, a pointer to a pathname.

• ioVRefNum

  On input, a volume specification.

• ioRefNum

  On output, a file reference number.

• ioPermssn

  On input, the read/write permission.

• ioDirID

  On input, a directory ID.

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

Generally your application should use Resource Manager functions rather than File Manager functions to access a file’s resource fork. The PBHOpenRFAsync 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.

AVAILABILITY

Supported in Carbon. Available in Mac OS 8.1 and later when Carbon 1.0.2 or later is present.

© 2000 Apple Computer, Inc. — (Last Updated 5/8/2000)