IAsyncReader::Length 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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 Length method retrieves the total length of the stream.
Syntax
HRESULT Length(
LONGLONG *pTotal,
LONGLONG *pAvailable
);
Parameters
pTotal
Pointer to a variable that receives the length of the stream, in bytes.
pAvailable
Pointer to a variable that receives the portion of the stream that is currently available, in bytes.
Return value
Returns an HRESULT value. Possible values include the following.
| Return code | Description |
|---|---|
|
Success. |
|
The returned values are estimates; for example, if the file is being read over a network. |
|
The file is not open or no longer exists. |
Remarks
For streams retrieved over a network, the entire stream may not be available at first. Read operations beyond the available length might block for a long period of time, until that portion of the stream becomes available.
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 |