定義
void pthread_exit(void* retval);
pthread_exit（）
參數
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
void *print_message_function( void *ptr )
{
char *message;
message = (char *) ptr;
printf("%s \t", message);
printf("PID: %ld \n", pthread_self());
pthread_exit ("thread all done"); // 重點看 pthread_exit() 的參數，是一個字串，這個參數的指針可以通過
// pthread_join( thread1, &pth_join_ret1);
}
main()
{
pthread_t thread1, thread2;
char *message1 = "Thread 1";
char *message2 = "Thread 2";
int iret1, iret2;
void *pth_join_ret1;//="thread1 has done!";
void *pth_join_ret2;//="thread2 has done!";
/* Create independant threads each of which will execute function */
//pthread_create return 0 if create a thread is ok!
iret1 = pthread_create( &thread1, NULL, print_message_function, (void*)"thread one_here");
iret2 = pthread_create( &thread2, NULL, print_message_function, (void*) message2);
pthread_join( thread1, &pth_join_ret1);
pthread_join( thread2, &pth_join_ret2);
//
//if(pth_join_ret1==NULL || pth_join_ret2==NULL)
//{
// printf("in %d lines \n",__LINE__);
//}
printf("Thread 1 returns: %d\n",iret1);
printf("Thread 2 returns: %d\n",iret2);
printf("pthread_join 1 returns: %s\n",(char *)pth_join_ret1);
printf("pthread_join 2 returns: %s\n",(char *)pth_join_ret2);//目的就是列印 執行緒退出時的返回值
exit(0);
}
//重點看上面紅色注釋。以前確實沒注意，今天幫一個新同事調試程式才仔細看了說明
DESCRIPTION
pthread_exit terminates the execution of the calling
thread. All cleanup handlers that have been set for the
calling thread with pthread_cleanup_push(3) are executed
in reverse order (the most recently pushed handler is exe-
cuted first). Finalization functions for thread-specific
data are then called for all keys that have non- NULL val-
ues associated with them in the calling thread (see
pthread_key_create(3)). Finally, execution of the calling
thread is stopped.
The retval argument is the return value of the thread. It
can be consulted from another thread using
pthread_join(3).
