#define N 4
typedef struct{
int index;
pthread_t *tid;
}mix;
void* thread_talk(void* input_value)
{
int index = (int)(long)input_value;
printf("In process %d, thread %u running, my index is %d\r\n",getpid(), (unsigned int)pthread_self(), (int)(long)input_value);
/*Join the thread based on the index of tid*/
printf("My index is %d, I receive the return value \r\n",index);
return (void*)(&index);
}
int thread_create(mix * input)
{
int ret;
int index = input->index;
printf("my index is %d\r\n",index);
if(input->index > 0)
{
pthread_join(input->tid[input->index - 1], (void *)&ret);
printf(“ret %d\r\n”,ret);
sleep(1);
}
pthread_create(&input->tid[input->index], NULL, thread_talk, (void*)(long)index);
printf("input->tid[input->index] %d\r\n",(unsigned int)input->tid[input->index]);
sleep(1);
return 0;
}
int main()
{
pthread_t tid[N];
mix input = {0, tid};
int i;
for(i = 0; i < N; i++)
{
input.index = i;
thread_create(&input);
}
while(1);
return 0;
}
输出结果如下：
老师，这是什么原因导致的呢？
当我改用地址传参时：如下
void* thread_talk(void* input_value)
{
int index = *(int *)input_value;
printf(“In process %d, thread %u running, my index is %d\r\n”,getpid(), (unsigned int)pthread_self(),index);
/*Join the thread based on the index of tid*/
printf("My index is %d, I receive the return value \r\n",index);
return (void*)(&index);
}
int thread_create(mix * input)
{
int ret;
int index = input->index;
printf(“my index is %d\r\n”,index);
if(input->index > 0)
{
pthread_join(input->tid[input->index - 1], (void )&ret);
printf(“ret %d\r\n”,ret);
sleep(1);
}
pthread_create(&input->tid[input->index], NULL, thread_talk, (void)&index);
printf(“input->tid[input->index] %d\r\n”,(unsigned int)input->tid[input->index]);
sleep(1);
return 0;
}
也出现了传递不对的情况
但是以下情况却能得到预期的结果
#define N 4
typedef struct{
int index;
pthread_t *tid;
}mix;
void* thread_talk(void* input_value)
{
int* ret;
mix *input = (mix *)input_value;
int index = input->index;
printf(“In process %d, thread %u running, my index is %d\r\n”,getpid(), (unsigned int)pthread_self(), index);
/*thread 0 won't join*/
if(input->index == 0){
printf("thread 0 will stop\r\n");
return (void*)0;
}
/*Join the thread based on the index of tid*/
pthread_join(input->tid[index - 1], (void *)&ret);
printf("My index is %d, I receive the return value %d\r\n",index,(int)ret);
return (void*)(input->index);
}
int thread_create(pthread_t* tid, int index)
{
mix input = {index, tid};
printf(“my index is %d\r\n”,index);
pthread_create(&tid[index], NULL, thread_talk, (void*)(&input));
sleep(1);
return 0;
}
int main()
{
pthread_t tid[N];
int i;
for(i = 0; i < N; i++)
thread_create(tid,i);
while(1);
return 0;
}
