我遇到此细分错误。

它将先运行第一种方法,然后运行第二种方法的printf行,然后直接运行到分段错误。
我不明白为什么...我重新分配了之前的分配。
我的第二个方法运行的那一刻,它将输出prinf语句:客户端然后分段错误

void
ThreadTest()
{

   DEBUG('t', "Entering SimpleTest");
   printf("THREAD TEST\n");

      Thread *s = new Thread("thread");
      s->Fork(client2,1);

      Thread *g = new Thread("thread");
      g->Fork(client, 1);


}


我的第一种方法正在运行

void
client2(int which)
{
  DEBUG('t', "Entering SimpleTest");


  printf("client2\n");

  int urlSize;
  const int sz = 50;
  char url[sz];

  FILE *fp = fopen("url.txt", "r");
  if (!fp)
    printf("  Cannot open file url.txt!\n");


  else {
    int pos = 0;

    char c = getc(fp);

    while (c != EOF || pos == sz - 1)
      {

    if (c == '\n')
      {
        url[pos] = '\0';
        //serve(url);
        pos = 0;
        //url size
        urlSize = sizeof(url)/sizeof(url[0]);

//---------------------------------------------------------------------------

        urlList = (List*)malloc(urlSize*sizeof(List));

//---------------------------------------------------------------------------


        clientTXT.P(); //wait
        mutex2.P();//entering critical region

        urlList -> Append(url);
        cout<<"urls: "<< url<<endl;

        mutex2.V();//leaving critical region
        clientURL.V();// increment slots or client url request objects

//--------------------------------------------------------------------------

        free(urlList);

//---------------------------------------------------------------------------


      }
    else
      {
        url[pos++] = c;
      }
    c = getc(fp);
      }
    fclose(fp);
    printf("No more URLs\n");
  }



}


第二种方法运行

void
client(int request)
{
  DEBUG('t', "Entering SimpleTest");
  printf("client\n");

  int urlSize;


  while(TRUE){

    char* nextUrl;
    printf("segment");
    nextUrl = (char*)urlList->Remove();

    urlSize = sizeof(nextUrl)/sizeof(nextUrl[0]);


    Request *reqq = new Request(nextUrl, urlSize, request, 1);
//---------------------------------------------------------------------------
    reqList = (List*)malloc(urlSize*sizeof(List));

    //--------------------------------------------------------
    clientURL.P(); //wait
    mutex.P();    //entering critical region

    reqList->Append(reqq);
    cout<<"urldest: "<<(reqq->urlDest)<<endl;

    mutex.V();     //exit critical region
    serverURL.V();  //signal
    //--------------------------------------------------------

    free(reqList);
//---------------------------------------------------------------------------

  }
}

最佳答案

因为您没有同步对urlList的访问,所以可能会出现此问题。
client2中,您要分配urlList,然后在client中对其进行访问,但是不能保证两个线程的执行顺序。考虑使用同步原语来控制对urlList的访问,以确保在访问它之前先对其进行分配。

关于c++ - 使用线程时出现段错误,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/26416671/

10-11 23:22
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