pthread_jion() , pthread_create() 导致的segmentation fault
下午调试程序的“segmentation fault”，先上代码：
int main() { printf("entering main() /n"); init_globals(); /*initialize global variable defined in main.c*/ init_iic(); init_spi(); if(init_sock() == -1){ exit(1); } sock_listen_tid = pthread_create(&sock_listen_tid,NULL,listen_thread,NULL); if( sock_listen_tid!= 0){ printf("pthread_create() error /n"); exit(1); } //sleep(10); pthread_join(sock_listen_tid,NULL); return 0; } void* listen_thread(void* arg) { //省略 return ((void*)0); }
左看右看找不到错在那，尝试去掉pthread_join, 竟然正常了。
注意这句：
sock_listen_tid = pthread_create(&sock_listen_tid,NULL,listen_thread,NULL);
pthread_create的返回值赋给了sock_listen_tid，这行代码看起来的确的确的确有些怪~
看函数说明 man 3 pthread_create
函数返回值描述如下：
RETURN VALUE
If successful, the pthread_create() function shall return zero; otherwise,
an error number shall be returned to indicate the error.
ERRORS
The pthread_create() function shall fail if:
EAGAIN The system lacked the necessary resources to create another thread,
or the system-imposed limit on the total number of threads in a
process {PTHREAD_THREADS_MAX} would be exceeded.
EINVAL The value specified by attr is invalid.
EPERM The caller does not have appropriate permission to set the required
scheduling parameters or scheduling policy.
The pthread_create() function shall not return an error code of [EINTR].
The following sections are informative.
如果创建成功, pthread_create将返回0. 赋值给sock_listen_tid等于0。然后执行pthread_join(0, NULL)，相当于等待线程号为0的线程，当然segmentation fault