Dynamic Memory Allocation

Module Description

The mem_Nnn functions provide solid heap management.
#include <uLib/MemFunc.h>

The mem_Alloc() and mem_Realloc() functions go to considerable length to succeed,
including coalescing the heap to satisfy failed allocations, and mem_Free()
wraps deallocation in SEH (compiler permitting) to avoid termination-by-mistake.

Groups
	Page Buffers
	Page aligned virtual memory.
	Physical Memory (AWE)
	Allocation of physical memory.

Classes
class	SharedMem
	Interprocess shared memory. More...

Functions
void *	mem_Alloc (size_t Bytes)
void *	mem_Realloc (void *pBlk, size_t Bytes)
void *	mem_Free (void *pBlk)
bool	mem_Compact ()

Variables
HANDLE	app_Heap

Function Documentation

mem_Alloc()

void* mem_Alloc

(

size_t

Bytes

)

Allocate a block from the app_Heap.

Parameters

Bytes

Size to allocate. If zero, a NULL pointer is returned.

Returns

The re/allocated block, or NULL.

Note: The mem_Alloc() and mem_Realloc() functions both try to coalesce the heap if an allocation fails,
and if a retry fails, validate the whole heap before they give up.

Definition at line 33 of file MemFunc.cpp.

mem_Realloc()

void* mem_Realloc	(	void *	pBlk,
		size_t	Bytes
	)

Reallocate an existing memory block.
Note: Guaranteed zero,null contract, forever.
(C23 'victims' will appreciate the age proven 'realloc' compliance.)

Parameters

pBlk	Block ptr. If NULL, mem_Alloc is invoked.
Bytes	Size to allocate. If zero, and pBlk is not null, invoke mem_Free.

Returns

The re/allocated block, or NULL.

See also

See mem_Alloc(). mem_Free().

Definition at line 80 of file MemFunc.cpp.

mem_Free()

void* mem_Free

(

void *

pBlk

)

Free a heap block and return NULL on success, or pBlk on error.
The deallocation is wrapped in SEH (compiler permitting) to avoid termination-by-mistake from invalid block pointers.
Note: mem_Free is NULL-safe.

Definition at line 124 of file MemFunc.cpp.

mem_Compact()

bool mem_Compact

(

)

mem_Compact() coalesces free blocks and decommits unused pages.
This is done using HeapCompact(), which is fairly expensive, so don't overuse.

Definition at line 150 of file MemFunc.cpp.

Variable Documentation

app_Heap

HANDLE app_Heap

The heap used by the mem_Nnn functions.
The app_Heap is globally initialized with GetProcessHeap during startup.
However, nothing prevents you from changing it with HeapCreate if you prefer a customized heap.
Just be sure to do it before using any mem_Nnn functions.

Definition at line 12 of file MemFunc.cpp.