c - 互斥锁上的随机错误

Question

互斥锁随机成功或失败，失败时会出现以下情况:

Invalid argument

或

tpp.c:62: __pthread_tpp_change_priority: Assertion `new_prio == -1 || (new_prio >= __sched_fifo_min_prio && new_prio <= __sched_fifo_max_prio)' failed.

代码非常基本，您可以在此处看到:

pthread_mutex_t mutex;
main() {
  int ret;
  pthread_mutexattr_t attr;
  pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
  ret = pthread_mutex_init(&mutex, &attr);
  if (ret != 0) {
    printf("pthread_mutex_init\n");
    return 1;
  }
  ret = pthread_mutex_lock(&mutex);
  if (ret != 0) {
    printf("mutex_lock failed %s\n", strerror(ret));
    return 1;
  }
  ret = pthread_mutex_unlock(&mutex);
  if (ret != 0) {
    printf("mutex_unlock failed %s\n", strerror(ret));
    return -1;
  }

这是为什么？

Answer 1

您没有初始化attr。其内容未定义。

参见pthread_mutexattr_init :

DESCRIPTION

The function pthread_mutexattr_init() initialises a mutex attributes object attr with the default value for all of the attributes defined by the implementation.