CBaseFilter::m_pLock member

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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.]

Pointer to a critical section that is used to serialize state changes.

Syntax

CCritSec *m_pLock;

Remarks

This variable is initialized in the class constructor; see CBaseFilter::CBaseFilter.

Hold this critical section during state transitions, or when a method accesses the state over several operations. The base class holds the critical section in the following methods:

• CBaseFilter::FindPin
• CBaseFilter::GetSyncSource
• CBaseFilter::JoinFilterGraph
• CBaseFilter::IsActive
• CBaseFilter::SetSyncSource
• CBaseFilter::Pause
• CBaseFilter::Run
• CBaseFilter::Stop

Do not hold this critical section during streaming operations (that is, when delivering samples to a downstream filter). Serialize streaming operations using a different critical section. Otherwise, it can cause deadlock.

Requirements

Requirement	Value
Header	Amfilter.h (include Streams.h)
Library	Strmbase.lib (retail builds); Strmbasd.lib (debug builds)

See also

CBaseFilter Class

Threads and Critical Sections