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Ê×ÏȽéÉÜÏÂpthread_cond_t¡£ ÔÚLinuxϳÆ֮Ϊ״̬±äÁ¿£¬ÓëÖ®Ïà¹ØµÄÓÐÏÂÃ漸¸öAPI:
    int pthread_cond_init (pthread_cond_t *COND,pthread_condattr_t *cond_ATTR);
    int pthread_cond_signal (pthread_cond_t *COND);
    int pthread_cond_broadcast (pthread_cond_t *COND);
    int pthread_cond_wait (pthread_cond_t *COND, pthread_mutex_t *MUTEX);
    int pthread_cond_timedwait (pthread_cond_t *COND, pthread_mutex_t *MUTEX, const struct timespec *ABSTIME);
    int pthread_cond_destroy (pthread_cond_t *COND);
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{
    pthread_mutex_lock(lock)
...
    pthread_cond_wait(cond, lock);
...
    pthread_cond_mutex_unlock(lock);
}
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{
    pthread_mutex_lock(lock);
...
    pthread_cond_signal(cond);
...
    pthread_mutex_unlock(lock);
}
pthread_cond_signalµ÷ÓÃ֮ǰһ¶¨»áÏÈÄõ½lockËø¡£pthread_cond_signal²»»áÈ¥¹ÜlockËø£¬Ö»Êǽ«cond¼¤»î£¬½ÓÏÂÈ¥ÊÍ·ÅlockËø¡£Õâʱºòpthread_cond_wait¾Í¿ÉÒԵõ½lock´Ó¶ø·µ»ØÁË¡£
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typedef struct pthread_rwlock
{
int active_readers; /* -1 when writer lock locked, >0 when read lock locked */
int pending_readers;
int pending_writers;
pthread_mutex_t mutex;
pthread_cond_t ok_to_read;
pthread_cond_t ok_to_write;
} pthread_rwlock_t ;
int pthread_rwlock_init(pthread_rwlock_t * lock, pthread_rwlockattr_t *attr)
{
active_readers = 0;
pending_readers = 0;
pending_writers = 0;
pthread_mutex_init(&lock->mutex, NULL);
pthread_cond_init(&lock->ok_to_read, NULL);
pthread_cond_init(&lock->ok_to_write, NULL)