diff options
| -rw-r--r-- | common/system.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/common/system.h b/common/system.h index a55bc2b543..7246389bab 100644 --- a/common/system.h +++ b/common/system.h @@ -750,6 +750,8 @@ public: * But since those may be implemented using threads (and in fact, that's * how our primary backend, the SDL one, does it on many systems), we * still have to do mutex syncing in our timer callbacks. + * In addition, the sound mixer uses a mutex in case the backend runs it + * from a dedicated thread (as e.g. the SDL backend does). * * Hence backends which do not use threads to implement the timers simply * can use dummy implementations for these methods. @@ -766,6 +768,12 @@ public: /** * Lock the given mutex. + * + * @note ScummVM code assumes that the mutex implementation supports + * recursive locking. That is, a thread may lock a mutex twice w/o + * deadlocking. In case of a multilock, the mutex has to be unlocked + * as many times as it was locked befored it really becomes unlocked. + * * @param mutex the mutex to lock. */ virtual void lockMutex(MutexRef mutex) = 0; |