HOpen

Open the data fork of a file

#include <Files.h> File Manager (PBxxx)

OsErr HOpen( vRefNum, dirID, fileName, permission, refNum );

short vRefNum; volume or working directory refNum (0 = default)

long dirID; directory ID of volume containing file

Str255 fileName; address of full/partial path/file name

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

short * refNum; returns file reference number

returns Error Code; 0=no error

HOpen opens the data fork of a file, enabling I/O operations. It is

functionally equivalent to FSOpen, but you can specify a File Permission

level.

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

noErr (0) No error

bdNamErr (-37) Bad name

extFSErr (-58) External file system

fnfErr (-43) File not found

ioErr (-36) I/O error

nsvErr (-35) No such volume

opWrErr (-49) File already open for writing

permErr (-54) Attempt to open locked file

tmfoErr (-42) Too many files open

Notes: The permission field specifies read-only, read/write, and sharing

options. 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.

Use PBOpenRF for direct access to the resource fork of a file.

The most common way to obtain ioNamePtr and ioVRefNum is by using the

Standard File Package, as illustrated in this example. See FSOpen for

related information and a similar example.

Referenced by (5):