nsz Git - musl/blob - src/thread/pthread_mutex_trylock.c

   1 #include "pthread_impl.h"
   2
   3 int pthread_mutex_trylock(pthread_mutex_t *m)
   4 {
   5         pthread_t self;
   6         if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
   7                 self = pthread_self();
   8                 if (m->_m_type == PTHREAD_MUTEX_RECURSIVE
   9                  && m->_m_owner == self->tid) {
  10                         if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
  11                         m->_m_count++;
  12                         return 0;
  13                 }
  14         }
  15
  16         if (a_xchg(&m->_m_lock, 1))
  17                 if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK
  18                  && m->_m_owner == self->tid) return EDEADLK;
  19                 else return EBUSY;
  20         if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
  21                 m->_m_owner = self->tid;
  22                 m->_m_count = 1;
  23         }
  24         return 0;
  25 }