PDD_FREEDRIVERMEMORY callback function (ddrawint.h)
The DdFreeDriverMemory callback function frees offscreen or nonlocal display memory to satisfy a new allocation request.
Syntax
PDD_FREEDRIVERMEMORY PddFreedrivermemory;
DWORD PddFreedrivermemory(
PDD_FREEDRIVERMEMORYDATA unnamedParam1
)
{...}
Parameters
unnamedParam1
Points to a DD_FREEDRIVERMEMORYDATA structure that contains the details of the free request.
Return value
DdFreeDriverMemory returns one of the following callback codes:
Remarks
The driver should implement DdFreeDriverMemory when it has DirectDraw manage all offscreen display memory management, including allocations for DrvCreateDeviceBitmap. DirectDraw requests for allocations in offscreen memory should always take precedence over GDI device bitmap allocations.
DirectDraw calls DdFreeDriverMemory when it does not have enough offscreen or nonlocal display memory to allocate a surface requested by an application. The driver should move a GDI device bitmap from offscreen memory into system memory and then immediately return. Bitmap moves can be accomplished by calling EngModifySurface.
DirectDraw will continually call DdFreeDriverMemory until there is enough offscreen memory from which to allocate the requested surface or until the driver returns DDERR_OUTOFMEMORY.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Desktop |
| Header | ddrawint.h (include Winddi.h) |