linux 线程练习

#include 
#include 
#include 

#include 
#include 
#include 
#include 

#define ERR_EXIT(m) \
        do \
        { \
                perror(m); \
                exit(EXIT_FAILURE); \
        } while(0)

void* thread_routine(void *arg)
{
	int i;
        for (i=0; i<20; i++)
        {
                printf("B");
                fflush(stdout);
		usleep(20);
/*
		if (i==3)
			pthread_exit("ABC");
*/
        }
	sleep(3);
	return "DEF";
}

int main(void)
{
	pthread_t tid;
	int ret;
	if ((ret = pthread_create(&tid, NULL, thread_routine, NULL)) != 0)
	{
		fprintf(stderr, "pthread_create:%s\n", strerror(ret));
		exit(EXIT_FAILURE);
	}

	int i;
	for (i=0; i<20; i++)
	{
		printf("A");
		fflush(stdout);
		usleep(20);
	}

	void *value;
	if ((ret = pthread_join(tid, &value)) != 0)
	{
		fprintf(stderr, "pthread_join:%s\n", strerror(ret));
		exit(EXIT_FAILURE);
	}
	printf("\n");

	printf("return msg=%s\n", (char*)value);

	return 0;
}