Linux下多线程问题，求大侠指教

[zhuaibing]

问题如下：
有100个同样任务的队列，想用5个线程完成它

int x;

void* output( void* arg )
{
while(1) {

if (x >100) return NULL;
printf( "I am thread %d, Hello World! %d \n", pthread_self(),x++ );
sleep(3);
}
//return NULL;
}

int main( int argc, char** argv )
{
pthread_t tid[5] = { 0 };
int i = 0;
x=0;
for( i = 0; i < 5; i++ )
{
if( errno = pthread_create( tid + i, NULL, output, NULL ) )
{
fprintf( stderr, "failed to create thread: %s\n", strerror( errno ) );
return 1;
}
sleep(1); //时间设置不同结果运行不同
}

/*
for( i = 0; i < 5; i++ )
{
if( errno = pthread_join( tid[i], NULL ) )
{
fprintf( stderr, "failed to waite thread: %s\n", strerror( errno ) );
return 1;
}
}
*/
return 0;

}

编译运行结果如下：
I am thread 134558720, Hello World! 0
I am thread 134559232, Hello World! 1
I am thread 134558720, Hello World! 2
I am thread 134559744, Hello World! 3
I am thread 134559232, Hello World! 4
I am thread 134558720, Hello World! 5
I am thread 134560256, Hello World! 6
I am thread 134559744, Hello World! 7
I am thread 134559232, Hello World! 8
I am thread 134560768, Hello World! 9
I am thread 134558720, Hello World! 10
I am thread 134560256, Hello World! 11
I am thread 134559744, Hello World! 12


x还没到100，为什么就结束了啊，求大侠指教一下，谢谢！

[jackyzhu_001]

主程序退出，线程也就不存在了，呵呵
........
int x;

void* output( void* arg )
{
while(1) {

if (x >20)
pthread_exit((void *)3);
//return NULL;
printf( "I am thread %d, Hello World! %d \n", pthread_self(),x++ );
sleep(3);
}
//return NULL;
}

int main( int argc, char** argv )
{
pthread_t tid[5] = { 0 };
int i = 0;
x=0;
void *tret[5];

for( i = 0; i < 5; i++ )
{
if( errno = pthread_create( tid + i, NULL, output, NULL ) )
{
fprintf( stderr, "failed to create thread: %s\n", strerror( errno ) );
//return 1;
}
sleep(1);
}


for( i = 0; i < 5; i++ )
{
if( errno = pthread_join( tid[i], &tret[i] ) )
{
fprintf( stderr, "failed to waite thread: %s\n", strerror( errno ) );
return 1;
}
}

int j=0;
while(1)
{

for(i=0;i<5;i++)
if((int)tret[i] == 3) { printf("thread %d exit \n",i);j++ ;};
if(j == 5) break;
sleep(1);
}
return 0;

}

[softwarewander]

1楼的已经说清楚了， 你的主程序，都退出了， 当然就不可能看到hello word 100了

想要看到，最简单的就多让主程序sleep吧