IMemAllocatorCallbackTemp::GetFreeCount method (strmif.h)
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The GetFreeCount method returns the number of free media samples. This number equals the total number of media samples minus the number of samples that are currently held by filters.
Syntax
HRESULT GetFreeCount(
[out] LONG *plBuffersFree
);
Parameters
[out] plBuffersFree
Pointer to a variable that receives the number of free media samples.
Return value
Returns an HRESULT value. Possible values include the following.
| Return code | Description |
|---|---|
|
NULL pointer argument |
|
Success |
Remarks
A filter holds a sample by keeping a reference count on it. It releases the sample by releasing the reference count.
Until the allocator is committed, the samples are not guaranteed to be allocated.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | strmif.h (include Dshow.h) |
| Library | Strmiids.lib |