LocalInit

Initializes a local heap within a specified memory segment.

BOOL LocalInit(
  WORD  wSegment,
  WORD  wOffset,
  WORD  wHeapSize
);

• wSegment - The selector of the segment in which to initialize the local heap.
• wOffset - The offset within the segment at which the heap should start.
• wHeapSize - The size, in bytes, of the heap to initialize.

• Returns non-zero if the heap is successfully initialized.
• Returns 0 if initialization fails.

• LocalInit

  is specific to the 16-bit Windows environment and is not supported in Win32 or later.

• The function sets up a local heap manager within the provided segment, enabling local memory allocation functions to operate within that segment.
• Applications typically call

  LocalInit

  during initialization of a data segment or a dynamically allocated memory block intended for use as a local heap.

• The heap size (

  wHeapSize

  ) must be large enough to accommodate heap management overhead.

• For compatibility and performance reasons, modern Windows applications should use the standard heap functions (e.g.,

  HeapCreate

  ,

  HeapAlloc

  ) instead.

#include <windows.h>
 
BOOL InitializeLocalHeap(WORD seg, WORD offset, WORD size) {
    return LocalInit(seg, offset, size);
}

; Assume AX = segment, DX = offset, CX = heap size
push cx          ; wHeapSize
push dx          ; wOffset
push ax          ; wSegment
call LocalInit   ; Returns AX = non-zero if success

• LocalAlloc - Allocates memory from the local heap.
• LocalFree - Frees memory allocated from the local heap.
• LocalSize - Retrieves the size of a local memory block.
• LocalReAlloc - Reallocates a local memory block.