Declaration

function StackAlloc(Size: Integer): Pointer; register;
procedure StackFree(P: Pointer); register;

Parameters

Parameter	Type	Description
Size	Integer	The number of bytes to allocate on the stack.
P	Pointer	Pointer to the stack-allocated memory block to free.

Returns

Type	Description
Pointer	Returns a pointer to the stack-allocated memory buffer.

Description

StackAlloc provides rapid allocation of small temporary memory blocks directly from the call stack by adjusting the stack pointer. This achieves allocation performance equivalent to local variables while allowing dynamic runtime buffer sizing.

StackFree releases the memory allocated by StackAlloc.

Remarks

• StackFree must be called in the exact same stack context as StackAlloc (not inside a nested subroutine or finally block).
• Multiple StackFree calls must occur in reverse order of their corresponding StackAlloc calls.
• If USESTACKALLOC is disabled or pure Pascal mode is active, StackAlloc transparently falls back to GetMem / FreeMem heap allocation.