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Inside Macintosh: Memory /

Chapter 2 - Memory Manager / Memory Manager Reference

Memory Manager Routines / Allocating and Releasing Relocatable Blocks of Memory

NewEmptyHandle

If you want to initialize a handle but not allocate any space for it, use the NewEmptyHandle function. The Resource Manager uses this function extensively,
but you probably won't need to use it.

FUNCTION NewEmptyHandle: Handle;

DESCRIPTION

The NewEmptyHandle function initializes a new handle by allocating a master pointer for it, but it does not allocate any memory for the handle to control. NewEmptyHandle sets the handle's master pointer to NIL.

SPECIAL CONSIDERATIONS

Because NewEmptyHandle might need to call the MoreMasters procedure to
allocate new master pointers, it might allocate memory. Thus, you should not call NewEmptyHandle at interrupt time.

ASSEMBLY-LANGUAGE INFORMATION

The registers on exit for NewEmptyHandle are

Registers on exit
A0	Address of the new block's master pointer
D0	Result code

You can specify that the NewEmptyHandle function apply to the system heap zone instead of the current zone. To do so, set bit 10 of the routine trap word. In most development systems, you can do this by supplying the word SYS as the second argument to the routine macro, as follows:

_NewEmptyHandle ,SYS

RESULT CODES

noErr	0	No error
memFullErr	-108	Not enough memory

SEE ALSO

When you want to allocate memory for the empty handle, use the ReallocateHandle procedure, described on page 2-52.