All Databases Inside Mac - Basic Toolbox

HOpenRF

Open the resource fork of an existing file

#include <Files.h> File Manager

OSErr HOpenRF( vRefNum, dirID, fileName, permission, frefNum );

short vRefNum ; volume or directory reference number

long dirID; ID of directory where that file resides in

Str255 fileName ; address of length-prefixed full or partial name

SignedByte permission; File Permission (1 = read, 2 = write, etc.)

short *fRefNum ; receives file reference number

returns Error Code; 0=no error

HOpenRF opens the resource fork of an existing file. Resources are

normally accessed via the Resource Manager functions such as LoadResource,

GetResource, GetCursor, etc., that manage the resource map and other

details automatically. It is functionally equivalent to OpenRF, except that

you can specify a File Permission level. About the only reason to use HOpenRF

is to perform a file-copy operation.

vRefNum is the reference number of the volume or directory containing

fileName . See FSOpen for the various options.

dirID is the directory ID of the directory that the file resides in.

fileName is the address of a length-prefixed, pascal-style string containing

the name of the file to be opened. It may be a partial or full

pathname, depending upon the value of vRefNum .

permission indicates the access permission level that the file should be opened

with. See the Notes section below for the constants that can be used in

this field

fRefNum is the address of a 16-bit short. Upon return, it will contain the

file reference number (also called the access path number) of the

file's resource fork. This value is used in all subsequent operations

on the open file.

Returns: an operating system Error Code. It will be one of:

noErr (0) No error

bdNamErr (-37) Bad name

extFSErr (-58) External file system

ioErr (-36) I/O error

nsvErr (-35) No such volume

opWrErr (-49) File already open with for writing

tmfoErr (-42) Too many files open

Notes: HOpenRF takes a permission parameter. In most cases, you can simply

set the permission parameter to fsCurPerm. Some applications request

fsRdWrPerm, to ensure that they can both read and write to a file. The

constants that can be passed in this parameter are the following:

fsCurPerm exclusive read/write permission if it is available;

otherwise, exclusive read, if that is available

fsRdPerm exclusive read permission

fsWrPerm exclusive write permission

fsRdWrPerm exclusive read/write permission

fsRdWrShPerm shared read/write permission

In shared environments, permission requests are translated into the

"deny-mode" permissions defined by AppleShare.

Referenced by (3):