Diffstat (limited to 'qmake/tools/qwaitcondition_unix.cpp') (more/less context) (ignore whitespace changes)
| -rw-r--r-- | qmake/tools/qwaitcondition_unix.cpp | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/qmake/tools/qwaitcondition_unix.cpp b/qmake/tools/qwaitcondition_unix.cpp index 99c1014..6684617 100644 --- a/qmake/tools/qwaitcondition_unix.cpp +++ b/qmake/tools/qwaitcondition_unix.cpp @@ -79,97 +79,97 @@ struct QWaitConditionPrivate { // Key was pressed, do something interesting do_something(); } \endcode A fourth thread would read key presses and wake the other three threads up every time it receives one, like this: \code QWaitCondition key_pressed; for (;;) { getchar(); // Causes any thread in key_pressed.wait() to return from // that method and continue processing key_pressed.wakeAll(); } \endcode Note that the order the three threads are woken up in is undefined, and that if some or all of the threads are still in do_something() when the key is pressed, they won't be woken up (since they're not waiting on the condition variable) and so the task will not be performed for that key press. This can be avoided by, for example, doing something like this: \code QMutex mymutex; QWaitCondition key_pressed; int mycount=0; // Worker thread code for (;;) { key_pressed.wait(); // This is a QWaitCondition global variable mymutex.lock(); mycount++; mymutex.unlock(); do_something(); mymutex.lock(); mycount--; mymutex.unlock(); } // Key reading thread code for (;;) { getchar(); mymutex.lock(); // Sleep until there are no busy worker threads - while( count > 0 ) { + while( mycount > 0 ) { mymutex.unlock(); sleep( 1 ); mymutex.lock(); } mymutex.unlock(); key_pressed.wakeAll(); } \endcode The mutexes are necessary because the results of two threads attempting to change the value of the same variable simultaneously are unpredictable. */ /*! Constructs a new event signalling, i.e. wait condition, object. */ QWaitCondition::QWaitCondition() { d = new QWaitConditionPrivate; int ret = pthread_cond_init(&d->cond, NULL); #ifdef QT_CHECK_RANGE if (ret) qWarning( "Wait condition init failure: %s", strerror( ret ) ); #endif } /*! Deletes the event signalling, i.e. wait condition, object. */ QWaitCondition::~QWaitCondition() { int ret = pthread_cond_destroy(&d->cond); if (ret) { #ifdef QT_CHECK_RANGE qWarning( "Wait condition destroy failure: %s", strerror( ret ) ); #endif // seems we have threads waiting on us, lets wake them up pthread_cond_broadcast(&d->cond); } delete d; } @@ -179,132 +179,137 @@ QWaitCondition::~QWaitCondition() that is woken up depends on the operating system's scheduling policies, and cannot be controlled or predicted. \sa wakeAll() */ void QWaitCondition::wakeOne() { int ret = pthread_cond_signal(&d->cond); #ifdef QT_CHECK_RANGE if (ret) qWarning("Wait condition wakeOne failure: %s", strerror(ret)); #endif } /*! This wakes all threads waiting on the QWaitCondition. The order in which the threads are woken up depends on the operating system's scheduling policies, and cannot be controlled or predicted. \sa wakeOne() */ void QWaitCondition::wakeAll() { int ret = pthread_cond_broadcast(&d->cond); #ifdef QT_CHECK_RANGE if (ret) qWarning("Wait condition wakeAll failure: %s", strerror(ret)); #endif } /*! Wait on the thread event object. The thread calling this will block until either of these conditions is met: \list \i Another thread signals it using wakeOne() or wakeAll(). This function will return TRUE in this case. \i \a time milliseconds has elapsed. If \a time is ULONG_MAX (the default), then the wait will never timeout (the event must be signalled). This function will return FALSE if the wait timed out. \endlist \sa wakeOne(), wakeAll() */ bool QWaitCondition::wait(unsigned long time) { - pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; + pthread_mutex_t mutex; + pthread_mutex_init( &mutex, 0 ); + pthread_mutex_lock( &mutex ); int ret; if (time != ULONG_MAX) { struct timeval tv; gettimeofday(&tv, 0); timespec ti; - ti.tv_nsec = (tv.tv_usec * 1000) + (time % 1000) * 1000; + ti.tv_nsec = ( tv.tv_usec + ( time % 1000 ) * 1000 ) * 1000; ti.tv_sec = tv.tv_sec + (time / 1000) + ( ti.tv_nsec / 1000000000 ); ti.tv_nsec %= 1000000000; ret = pthread_cond_timedwait(&d->cond, &mutex, &ti); } else ret = pthread_cond_wait(&d->cond, &mutex); #ifdef QT_CHECK_RANGE if (ret && ret != ETIMEDOUT) qWarning("Wait condition wait failure: %s",strerror(ret)); #endif + pthread_mutex_unlock( &mutex ); + pthread_mutex_destroy( &mutex ); + return (ret == 0); } /*! \overload Release the locked \a mutex and wait on the thread event object. The \a mutex must be initially locked by the calling thread. If \a mutex is not in a locked state, this function returns immediately. If \a mutex is a recursive mutex, this function returns immediately. The \a mutex will be unlocked, and the calling thread will block until either of these conditions is met: \list \i Another thread signals it using wakeOne() or wakeAll(). This function will return TRUE in this case. \i \a time milliseconds has elapsed. If \a time is ULONG_MAX (the default), then the wait will never timeout (the event must be signalled). This function will return FALSE if the wait timed out. \endlist The mutex will be returned to the same locked state. This function is provided to allow the atomic transition from the locked state to the wait state. \sa wakeOne(), wakeAll() */ bool QWaitCondition::wait(QMutex *mutex, unsigned long time) { if (! mutex) return FALSE; if (mutex->d->type() == Q_MUTEX_RECURSIVE) { #ifdef QT_CHECK_RANGE qWarning("Wait condition warning: using recursive mutexes with\n" " wait conditions is undefined!"); #endif return FALSE; } int ret; if (time != ULONG_MAX) { struct timeval tv; gettimeofday(&tv, 0); timespec ti; - ti.tv_nsec = (tv.tv_usec * 1000) + (time % 1000) * 1000; + ti.tv_nsec = ( tv.tv_usec + ( time % 1000 ) * 1000 ) * 1000; ti.tv_sec = tv.tv_sec + (time / 1000) + ( ti.tv_nsec / 1000000000 ); ti.tv_nsec %= 1000000000; ret = pthread_cond_timedwait(&d->cond, &mutex->d->handle, &ti); } else ret = pthread_cond_wait(&d->cond, &mutex->d->handle); #ifdef QT_CHECK_RANGE if (ret && ret != ETIMEDOUT) qWarning("Wait condition wait failure: %s",strerror(ret)); #endif return (ret == 0); } #endif // QT_THREAD_SUPPORT |