好吧，我想了解线程

Question

有人可以帮助我吗？我想很清楚我在这里尝试用线程做什么。给我一些建议，有人请编译。我认为或者使用线程id指针会出现问题。

#include<stdio.h>
#include<pthread.h>
#include<stdlib.h>
#define NUM_THREADS 5

int main(int argc,char * argv[])
    {
      pthread_t threads(NUM_THREADS);
      int rc,t;
      for(t=0;t<NUM_THREADS;t++)
       {
        printf("In main: creating thread %d \n", t);
        rc=ptrhead_create(&threads(t),NULL,PrintHello,(void*),t); 
         if(rc)
          {
            printf("Error;pthread_create() returned %d \n",rc);
            exit(-1);
           }
            ptrhead_exit(NULL);

            }

  struct thread_data
   {
    int thread_id;
    int sum;
    char *message;
   };
     void *PrintHello(void *threadarg)
      {
       struct thread_data *mydata;
       my_data=(struct thread_data *) threadarg;
       taskid=my_data->thread_id;
       sum=my_data->sum;
       hello_msg=my_data->message;
       }

          int *taskids(NUM_THREADS);
          for(t=0;t<NUM_THREADS;t++)
            {
              taskids(t)=(int *) malloc(sizeof(int));
              *taskids(t)=t;
              printf("Creating thread %d \n", t);
    rc=pthread_create(&threads(t),NULL,PrintHello,(void*) taskids(t));
             }

            void *PrintHello(void *threadid)
                  }
               int id;
               tid=(int)threadid;
               printf("Hello World!!! It's me, thread #%d\n", tid);
               pthread_exit(NULL);
                  }