将多个值返回到C中的线程时出错

我设置了几个线程，每个线程都将填充多个值，并且应该向数据库查询并返回多个值。

单线程可以显示正确的值，但是当它们将值返回到主函数时出了点问题。

主要功能是：

for(int i=0; i<n; i++){
    struct thread_args* args = malloc(sizeof(*args));
    args->str = str;
    args->tri_input = tri_input;
    args->length = length;
    res = pthread_create(&t_id[i], NULL, threads, args);
    if(res != 0)
        printf("Failed to create %d th thread.\n", i);
}

for(int i=0; i<n; i++){
    void *returnRes;
    pthread_join(t_id[i], &returnRes);
    indicesArr[i] = returnRes;
    printf("in main thread, indicesArr[%d].length: %d\n", i, indicesArr[i] -> length);
}

单线程：

void *threads(void *args_){

    struct thread_args *args = (struct thread_args *)args_;
    char* str = args -> str;
    struct IntArrLenArr* indicesArr = NULL;
    indicesArr = malloc(sizeof(*indicesArr));
    int length = args -> length;
    PGconn *dbconn = DBconnect(str);
    *indicesArr = duncitonReturnIndicesArr(dbconn);
    printf("in threads, indicesArr -> length: %d\n", indicesArr->length);
    free(args);
    PQfinish(dbconn);
    return indicesArr;
}

结果如下：

in threads, indicesArr -> length: 0
in threads, indicesArr -> length: 0
in threads, indicesArr -> length: 4
in threads, indicesArr -> length: 0
in threads, indicesArr -> length: 0
in threads, indicesArr -> length: 4
in threads, indicesArr -> length: 4
in threads, indicesArr -> length: 0
in main threads, indicesArr[0].length: -1949512500
in threads, indicesArr -> length: 2
in threads, indicesArr -> length: 4
in threads, indicesArr -> length: 4
in threads, indicesArr -> length: 1
in threads, indicesArr -> length: 4

Process returned -1073741819 (0xC0000005)   execution time : 6.551 s
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如果它是由mingw64在win10上编译的，则看起来效果很好，但是我必须以某种方式将其编译为32位。我的IDE是代码块，从mingw64不同，我不得不添加一个链接MinGW\lib\libpthread_s.dll.a，并MinGW\lib\libpthread.a在那里当我的mingw32编译。我不知道这可能是问题吗？我该如何解决？