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Inside Macintosh: Files /

Chapter 2 - File Manager / File Manager Reference

Low-Level Volume Access Routines / Manipulating the Default Volume

PBHGetVol

You can use the PBHGetVol function to determine the default volume and default directory.

FUNCTION PBHGetVol (paramBlock: WDPBPtr; async: Boolean): OSErr;

paramBlock

A pointer to a working directory parameter block.

async

A Boolean value that specifies asynchronous (TRUE) or synchronous (FALSE) execution.

-->	ioCompletion	ProcPtr	A pointer to a completion routine.
<--	ioResult	OSErr	The result code of the function.
<--	ioNamePtr	StringPtr	A pointer to a pathname.
<--	ioVRefNum	Integer	A volume reference number or a working directory reference number.
<--	ioWDProcID	LongInt	The working directory user identifier.
<--	ioWDVRefNum	Integer	The volume reference number of the default volume.
<--	ioWDDirID	LongInt	The directory ID of the default directory.

DESCRIPTION

The PBHGetVol function returns the default volume and directory last set by a call
to either PBSetVol or PBHSetVol. The reference number of the default volume is returned in ioVRefNum. The PBHGetVol function returns a pointer to the volume's name in the ioNamePtr field. You should pass a pointer to a Str31 value if you
want that name returned. If you pass NIL in the ioNamePtr field, no volume name
is returned.

WARNING

On exit, the ioVRefNum field contains a working directory reference number (instead of the volume reference number) if, in the last call to PBSetVol or PBHSetVol, a working directory reference number was passed in this field.

The volume reference number of the volume on which the default directory exists
is returned in ioWDVRefNum. The directory ID of the default directory is returned
in ioWDDirID.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro for PBHGetVol is _HGetVol.

RESULT CODES

noErr	0	No error
nsvErr	-35	No default volume