c - C 中的线程加工错误？

Question

我编译了这段代码，它创建的第 99 个线程不断创建多个 99 号线程。相反，如果我插入 1-10 或较小的值，那么结果是相当正常的。

这是代码。

#include <stdio.h>
#include <pthread.h>
#include <unistd.h>

pthread_mutex_t m=PTHREAD_MUTEX_INITIALIZER;
pthread_attr_t attr;

void* test(void *a)
{
    int i=*((int *)a);
    printf("The thread %d has started.\n",i);
    pthread_mutex_lock(&m);
    usleep(10000);
    printf("The thread %d has finished.\n",i);
    pthread_mutex_unlock(&m);
    pthread_exit(NULL);

}

int main()
{
    int i=0,j=0;
    pthread_attr_setdetachstate(&attr,PTHREAD_CREATE_JOINABLE);
    pthread_t thread[100];

    for (i=0;i<100;i++)
    {
        j=i;
        pthread_create(&thread[i],&attr,test,&j);

    }

    for (i=0;i<100;i++)
        pthread_join(thread[i],NULL);
    return 0;
}

我得到:

..../*Normal Results*/
The thread 99 has finished.
The thread 99 has finished.
The thread 99 has finished.
The thread 99 has finished.
The thread 99 has finished.
The thread 99 has finished.

为什么会发生这种情况？

Answer 1

您需要保留所有theadId

int indexes[PTHREAD_COUNT];

for (i=0;i<100;i++) {
    indexes[i] = i;
    pthread_create(&thread[i], &attr, test, &indexes[i]);
}