SDL_CreateRWLock - Create a new read/write lock.
Contents
Availability
This function is available since SDL 3.2.0.
Description
A read/write lock is useful for situations where you have multiple threads trying to access a resource
that is rarely updated. All threads requesting a read-only lock will be allowed to run in parallel; if a
thread requests a write lock, it will be provided exclusive access. This makes it safe for multiple
threads to use a resource at the same time if they promise not to change it, and when it has to be
changed, the rwlock will serve as a gateway to make sure those changes can be made safely.
In the right situation, a rwlock can be more efficient than a mutex, which only lets a single thread
proceed at a time, even if it won't be modifying the data.
All newly-created read/write locks begin in the _unlocked_ state.
Calls to SDL_LockRWLockForReading () and
SDL_LockRWLockForWriting
will not return while the rwlock is locked _for writing_ by another thread. See
SDL_TryLockRWLockForReading () and
SDL_TryLockRWLockForWriting () to attempt to lock without blocking.
SDL read/write locks are only recursive for read-only locks! They are not guaranteed to be fair, or
provide access in a FIFO manner! They are not guaranteed to favor writers. You may not lock a rwlock for
both read-only and write access at the same time from the same thread (so you can't promote your read-
only lock to a write lock without unlocking first).
Header File
Defined in SDL3/SDL_mutex.h
Name
SDL_CreateRWLock - Create a new read/write lock.
Return Value
( SDL_RWLock
*) Returns the initialized and unlocked read/write lock or NULL on failure; call SDL_GetError () for
more information.
See Also
•(3), SDL_DestroyRWLock(3), •(3), SDL_LockRWLockForReading(3), •(3), SDL_LockRWLockForWriting(3), •(3), SDL_TryLockRWLockForReading(3), •(3), SDL_TryLockRWLockForWriting(3), •(3), SDL_UnlockRWLock(3) Simple Directmedia Layer SDL 3.2.10 SDL_CreateRWLock(3)
Synopsis
#include"SDL3/SDL.h"SDL_RWLock*SDL_CreateRWLock(void);
