Updates the resource map and resource data for a resource fork without closing it.

void UpdateResFile (
    SInt16 refNum
);

refNum

A file reference number for a resource fork. If there’s no open resource fork with the given reference number, the function does nothing, and the ResError function returns the result code resNotFound. If the value of the refNum parameter is 0, it represents the System file’s resource fork. If you call this function but the mapReadOnly attribute of the resource fork is set, the function does nothing, and the ResError function returns the result code resAttrErr.

DISCUSSION

Given the reference number of a file whose resource fork is open, this function performs three tasks. The first task is to change, add, or remove resource data in the file’s resource fork to match the resource map in memory. Changed resource data for each resource is written only if that resource’s resChanged bit has been set by a successful call to the ChangedResource or AddResource function. The UpdateResFile function calls the WriteResource function to write changed or added resources to the resource fork.

The second task is to compact the resource fork, closing up any empty space created when a resource was removed, made smaller, or made larger. If a resource is made larger, the Resource Manager writes it at the end of the resource fork rather than at its original location. It then compacts the space occupied by the original resource data. The actual size of the resource fork is adjusted when a resource is removed or made larger, but not when a resource is made smaller.

The third task is to write the resource map in memory to the resource fork if your application has called the ChangedResource function for any resource listed in the resource map or if it has added or removed a resource. All changes to resource information in the resource map become permanent at this time; if you want any of these changes to be temporary, you must restore the original information before calling UpdateResFile.

Because the CloseResFile function calls UpdateResFile before it closes the resource fork, you need to call UpdateResFile directly only if you want to update the file without closing it.

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)