Zone

Zone structure

#include <Memory.h>

typedef struct Zone { Size Offset Description

Ptr bkLim ; 4 0 Block limit; addr of byte after last in zone

Ptr purgePtr ; 4 4 (used internally)

Ptr hFstFree ; 4 8 First free master pointer

long zcbFree ; 4 12 Number of free bytes

ProcPtr gzProc ; 4 16 Address of grow zone proc (SetGrowZone)

short moreMast ; 2 20 Number of master ptrs to allocate at a time

short flags ; 2 22 (used internally)

short cntRel ; 2 24 (not used)

short maxRel ; 2 26 (not used)

short cntNRel ; 2 28 (not used)

short maxNRel ; 2 30 (not used)

short cntEmpty ; 2 32 (not used)

short cntHandles ; 2 34 (not used)

long minCBFree ; 4 36 (not used)

ProcPtr purgeProc ; 4 40 Address of purge warning procedure

Ptr sparePtr ; 4 44 (used internally)

Ptr allocPtr ; 4 48 (used internally)

short heapData ; 2 52 First byte of data in the zone

} Zone; 54 (size of this zone-prefix information)

typedef Zone *THz;

Notes: Several Memory manager calls require (or return) a THz (pointer to

Zone), including:

The global variable TheZone (at 0x0118) contains the address of the Zone

structure at the start of the current heap zone.

The gzProc field is set when you call InitZone or SetGrowZone. Set it to

NIL (0) if you don't care. This proc will be called when more space is

needed, as explained in SetGrowZone.

The zcbFree field contains the total number of free bytes in the zone. If the

zone is fragmented in the least, you won't be able allocate this much

memory in one block.

You can install a custom "purge warning procedure" by storing its address

in purgeProc. Note that purgeProc gets overwritten whenever you call

Referenced by (47):