Question

我在线路上遇到分段错误“pthread_t * tids =（pthread_t *）calloc（num_threads，sizeof（pthread_t））;”。我查看了一天的代码，但无法弄明白。我甚至删除了“子”功能中的所有内容，但它没有帮助。

int main(int argc, char* argv[]) {

    int sockfd, newsockfd, clilen;
    struct sockaddr_in serv_addr, cli_addr;
    int port_num, num_threads = 5;

    switch (argc) {
        case 3:
            num_threads = atoi(argv[2]);
        case 2:
            port_num = atoi(argv[1]);
            break;
        default:
            fprintf(stderr, "Usage: %s <port_number> <num_threads>\n", argv[0]);
            return -1;
            break;
    }
    queue_t *q;
    // the queue is unbounded if give a queue size of 0
    queue_init(&q, 0);  

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        perror("ERROR opening socket");
        return 1;
    }

    bzero((char*) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    serv_addr.sin_port = htons((short) port_num);

    if (bind(sockfd, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) < 0)
        perror("ERROR on binding");

    listen(sockfd,5);

printf("numofthreads: %d\n", num_threads);
    pthread_t* tids = (pthread_t*) calloc(num_threads, sizeof(pthread_t));
    if (tids == NULL) {
        printf("ERROR: failed to allocate memory!\n");
    }

    int i;

    //for (i = 0; i < num_threads; i++) {
        if (pthread_create(&tids[i], NULL, child, NULL)) {
            perror("ERROR");
            close(newsockfd);
            return 1;
        }
    //}

    while(1) {

        clilen = sizeof(cli_addr);
            newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
            if (newsockfd < 0)
                    perror("ERROR on accept");
        queue_push(q, newsockfd);

            //close(s_info.newsockfd); TODO

    }

    //clean up
    clean_up(q);
    free(tids);
    free(output_dir);

    return 0;
}

Answer 1

您正在访问未初始化的变量i：

    int i;

    //for (i = 0; i < num_threads; i++) {
        if (pthread_create(&tids[i], NULL, child, NULL)) {

访问未初始化的变量会导致未定义的行为。在这种情况下，它可能导致在第一个参数中传递给pthread_create()的无效指针，导致它在函数尝试取消引用指针时崩溃。

pthread_create给出了分段错误

1 个答案: