Legacy Document

Inside Macintosh: Memory /

Chapter 2 - Memory Manager / Memory Manager Reference

Memory Manager Routines / Assessing Memory Conditions

MaxBlock

Use the MaxBlock function to determine the size of the largest block you could allocate in the current heap zone after a compaction.

FUNCTION MaxBlock: LongInt;

DESCRIPTION

The MaxBlock function returns the maximum contiguous space, in bytes, that you could obtain after compacting the current heap zone. MaxBlock does not actually do the compaction.

ASSEMBLY-LANGUAGE INFORMATION

The registers on exit for MaxBlock are

Registers on exit
D0	Size of largest allocatable block

If you want to know the size of the largest allocatable block in the system heap zone, rather than in the current heap zone, 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:

_MaxBlock ,SYS

RESULT CODES

noErr

0

No error