Gets resource data for a resource specified by resource type and resource ID.

Handle GetResource (
    ResType theType, 
    SInt16 theID
);

theType

The resource type of the resource about which you wish to retrieve data.

theID

An integer that uniquely identifies the resource about which you wish to retrieve data.

If the function finds the specified resource entry in one of the resource maps and the entry contains a valid handle, it returns that handle. If the entry contains a a handle whose value is NULL, and if you haven’t called the SetResLoad function with the load parameter set to FALSE, GetResource attempts to read the resource into memory.

If the function can’t find the resource data, it returns NULL, and the ResError function returns the result code resNotFound. The GetResource function also returns NULL if the resource data to be read into memory won’t fit, in which case ResError returns an appropriate Memory Manager result code. If you call GetResource with a resource type that can’t be found in any of the resource maps of the open resource forks, the function returns NULL, but ResError returns the result code noErr. You should always check that the value of the returned handle is not NULL.

DISCUSSION

The function searches the resource maps in memory for the specified resource. The resource maps in memory, which represent all the open resource forks, are arranged as a linked list. When searching this list, the function starts with the current resource file and progresses through the list (that is, searching the resource maps in reverse order of opening) until it finds the resource’s entry in one of the resource maps.

Before reading the resource data into memory, the Resource Manager calls the Memory Manager to allocate a relocatable block for the resource data. The Memory Manager allocates the block, assigns a master pointer to the block, and returns to the Resource Manager a pointer to the master pointer. The Resource Manager then installs this handle in the resource map.

You can change the resource map search order by calling the UseResFile function before calling GetResource.

To include ROM-resident system resources in the Resource Manager’s search of the resource maps of open resource forks, use the RGetResource function.

SPECIAL CONSIDERATIONS

This function may move or purge memory blocks in the application heap. Your application should not call this function at interrupt time.

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)