c - 难以创建 Pthread(错误 22)

Question

了解 pthreads，但我无法创建它们。这是我的输出和 gdb 信息:

In main(), creating thread 1 ERROR: return code from pthread_create() is 22 for thread 1In main(), creating thread 2ERROR: return code from pthread_create() is 22 for thread 2In main(), creating thread 3ERROR: return code from pthread_create() is 22 for thread 3In main(), creating thread 4ERROR: return code from pthread_create() is 22 for thread 4In main(), creating thread 5ERROR: return code from pthread_create() is 22 for thread 5Program received signal SIGSEGV, Segmentation fault. 0xb7fb4d8a inpthread_join (threadid=76038327, thread_return=0x0)    at pthread_join.c:46 46 pthread_join.c: No such file or directory.

And here is my code:

#include <stdlib.h>
#include <stdio.h>
#include <strings.h>
#include <errno.h>
#include <pthread.h>
#include <unistd.h>

#define SBUFSIZE 1025

char errorstr[SBUFSIZE];
FILE* inputfp[5];

void* f(void* inpFile) {
    fprintf(stderr, "%s\n", (char*)inpFile);
    return NULL;
}

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

    int i;

    /* Thread Variables */
    pthread_attr_t attr;
    pthread_t *th[argc-2]; //one thread for each input file

    /* allocate memory for the threads */
    for (i = 0; i < (argc-2); i++) {
        th[i] = (pthread_t *) malloc(sizeof(pthread_t)); 
        inputfp[i] = fopen(argv[i], "r");
        if (!inputfp[i]) {
            sprintf(errorstr, "Error Opening Input File: %s", argv[i]);
            perror(errorstr);
        }
    }

    /* Create one thread for each input file */
    for (i = 1; i < (argc - 1); i++) {
        fprintf (stderr, "In main(), creating thread %1d\n", i);
        int rc = pthread_create (th[i], &attr, f, inputfp[i-1]);
        if (rc) {
            printf("ERROR: return code from pthread_create() is %d for thread %d\n",
                rc, i);
        }
    }

    /* wait for the threads to finish */
    for (i = 1; i < (argc - 1); i++) {
        pthread_join(*th[i], 0);
    }

    return EXIT_SUCCESS;
}

我错过了什么，但我不知道是什么。谁能帮忙？谢谢!

编辑:这是我根据 Joachim Pileborg 的建议更改代码的方法。我仍然收到从 pthread_create() 返回的错误 22，但 pthread_join 上的 SIGSEGV 错误不再发生。

有人对我如何让 pthread_create() 返回 0(表示线程创建成功)有任何建议吗？再次感谢!

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

    int i;

    /* Thread Variables */
    pthread_attr_t attr;
    pthread_t *th[argc-2]; //one thread for each input file

    /* allocate memory for the threads */
    for (i = 0; i < (argc-2); i++) {
        th[i] = (pthread_t *) malloc(sizeof(pthread_t)); 
        printf("%s\n", argv[i+1]);
        inputfp[i] = fopen(argv[i+1], "r");
        if (!inputfp[i]) {
            sprintf(errorstr, "Error Opening Input File: %s", argv[i]);
            perror(errorstr);
        }
    }

    /* Create one thread for each input file */
    for (i = 0; i < (argc - 2); i++) {
        fprintf (stderr, "In main(), creating thread %1d\n", i);
        int rc = pthread_create (th[i], &attr, f, inputfp[i]);
        if (rc) {
            printf("ERROR: return code from pthread_create() is %d for thread %d\n",
                rc, i);
        }
    }

    /* wait for the threads to finish */
    for (i = 0; i < (argc - 2); i++) {
        pthread_join(*th[i], 0);
    }

    return EXIT_SUCCESS;
}

Answer 1

您有一个循环，从零循环到 argc - 3，并使用正确的索引(从零到“数组大小减一”。

然后你有两个循环，从 1 循环到 argc - 2，并使用从 1 到“数组大小”的索引。

您应该在所有三个地方使用与第一个循环相同的循环。