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Inside Macintosh: Memory /

Chapter 3 - Virtual Memory Manager / Virtual Memory Manager Reference

Routines / Virtual Memory Management

UnholdMemory

To make a currently held range of memory eligible for paging again, use the UnholdMemory function.

FUNCTION UnholdMemory (address: UNIV Ptr; count: LongInt): OSErr;

address

The starting address of the range of memory to be released.

count

The size, in bytes, of the range of memory to be released.

DESCRIPTION

The UnholdMemory function makes the portion of the address space beginning at address and having a size of count bytes eligible for paging.

If the address parameter supplied to the UnholdMemory function is not on a page boundary, then it is rounded down to the nearest page boundary. Similarly, if the specified range does not end on a page boundary, the count parameter is rounded up so that the entire range of memory is released.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for the UnholdMemory function are

Trap macro	Selector
_MemoryDispatch	$0001

The registers on entry and exit for this routine are

Registers on entry
D0	Selector code
A0	Starting address
A1	Number of bytes to release

Registers on exit
D0	Result code

RESULT CODES

noErr	0	No error
paramErr	-50	Error in parameter list
notHeldErr	-621	Specified range of memory is not held
interruptsMaskedErr	-624	Called with interrupts masked