TRwFifoLock | Unreal Engine 5.7 Documentation

API > API/Runtime > API/Runtime/Chaos

A first-in, first-out "fair" read-write lock around a generic mutex Given a mutex (either just FCriticalSection or some custom lock) this class implements a fair lock. Any number of readers can enter the lock but as soon as a writer attempts to enter the lock all subsequent readers are forced to wait until the current readers leave the lock and the writer gets a chance to perform its operation. Once the write is completed the waiting readers are able to resume. This ensures we do not end up in a situation where we have a write waiting but many reads end up constantly forcing the write to wait. In a physics context a write on the game thread is time-critical and we want that thread to resume as soon as possible by pausing any reads (scene queries) until the write is finished


Name	TRwFifoLock
Type	class
Header File	/Engine/Source/Runtime/Experimental/Chaos/Public/Framework/Threading.h
Include Path	#include "Framework/Threading.h"

Syntax

template<typename MutexType>  
class TRwFifoLock

Constructors

Name	Remarks	Include Path	Unreal Specifiers
TRwFifoLock()		Framework/Threading.h

Destructors

Name	Remarks	Include Path	Unreal Specifiers
~TRwFifoLock()		Framework/Threading.h

Variables

Protected

Name	Type	Remarks	Include Path	Unreal Specifiers
Mutex	MutexType		Framework/Threading.h
NumReaders	std::atomic< uint32 >		Framework/Threading.h

Functions

Public

Name	Remarks	Include Path	Unreal Specifiers
void ReadLock()		Framework/Threading.h
void ReadUnlock()		Framework/Threading.h
void WriteLock()		Framework/Threading.h
void WriteUnlock()		Framework/Threading.h

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