From a1b8fa6071c609415bdfd9a47b7919d4c4de7b8b Mon Sep 17 00:00:00 2001 From: Sam Lantinga Date: Mon, 23 Apr 2018 21:50:03 -0700 Subject: [PATCH] TryLockMutex: Fix error handling for TryLockMutex Christian Herzig pthread_mutex_trylock() and by the way, pthread_mutex_lock() do not set errno. Pthread-methods directly return error code as int. See related man-pages for details. --- src/thread/pthread/SDL_sysmutex.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/src/thread/pthread/SDL_sysmutex.c b/src/thread/pthread/SDL_sysmutex.c index e7b5b5cec..e514778a5 100644 --- a/src/thread/pthread/SDL_sysmutex.c +++ b/src/thread/pthread/SDL_sysmutex.c @@ -116,6 +116,7 @@ int SDL_TryLockMutex(SDL_mutex * mutex) { int retval; + int result; #if FAKE_RECURSIVE_MUTEX pthread_t this_thread; #endif @@ -134,18 +135,20 @@ SDL_TryLockMutex(SDL_mutex * mutex) We set the locking thread id after we obtain the lock so unlocks from other threads will fail. */ - if (pthread_mutex_trylock(&mutex->id) == 0) { + result = pthread_mutex_trylock(&mutex->id); + if (result == 0) { mutex->owner = this_thread; mutex->recursive = 0; - } else if (errno == EBUSY) { + } else if (result == EBUSY) { retval = SDL_MUTEX_TIMEDOUT; } else { retval = SDL_SetError("pthread_mutex_trylock() failed"); } } #else - if (pthread_mutex_trylock(&mutex->id) != 0) { - if (errno == EBUSY) { + result = pthread_mutex_trylock(&mutex->id); + if (result != 0) { + if (result == EBUSY) { retval = SDL_MUTEX_TIMEDOUT; } else { retval = SDL_SetError("pthread_mutex_trylock() failed");