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Inside Macintosh: Memory /

Chapter 2 - Memory Manager / Memory Manager Reference

Memory Manager Routines / Changing the Sizes of Relocatable and Nonrelocatable Blocks

SetHandleSize

You can use the SetHandleSize procedure to change the logical size of the relocatable block corresponding to a handle.

PROCEDURE SetHandleSize (h: Handle; newSize: Size);

h

A handle to a relocatable block.

newSize

The desired new logical size, in bytes, of the relocatable block.

DESCRIPTION

The SetHandleSize procedure attempts to change the logical size of the relocatable block whose handle is h. The new logical size is specified by newSize. SetHandleSize might need to move the relocatable block to obtain enough space for the resized block. Thus, for best results you should unlock a block before resizing it.

An attempt to increase the size of a locked block might fail, because of blocks above and below it that are either nonrelocatable or locked. You should be prepared for this possibility.

SPECIAL CONSIDERATIONS

Because SetHandleSize allocates memory, you should not call it at interrupt time.

ASSEMBLY-LANGUAGE INFORMATION

The registers on entry and exit for SetHandleSize are

Registers on entry
A0	Handle to the relocatable block
D0	Desired new size of relocatable block

Registers on exit
D0	Result code

RESULT CODES

noErr	0	No error
memFullErr	-108	Not enough memory
nilHandleErr	-109	NIL master pointer
memWZErr	-111	Attempt to operate on a free block

SEE ALSO

Instead of using the SetHandleSize procedure to set the size of a handle to 0, you can use the EmptyHandle procedure, described on page 2-51.