Question

当我调用sem_post()函数时，我遇到了分段错误的问题。这是我的代码（检查超时）：

父线程：

void * Client::Init(void * args)
{
    char * clientIP;
    // clientIP = ... IP from other program part

    int * timeoutSemaphoreValue;

    sem_unlink(clientIP); // always new semaphore

    sem_t * semaphore;
    semaphore = sem_open(clientIP, O_CREAT | O_EXCL, O_RDWR, 0);

    if(errno == EEXIST)
         cout << "Problem z synchronizacją wątków (semafory) - nieobsłużone." << endl;

    pthread_create(&clientStatesThread, NULL, VOID_T Client::ClientStatesLoop, clientIP);

    while(status > 0)
    {   
         sem_getvalue(semaphore, timeoutSemaphoreValue);

         if(*(client->timeoutSemaphoreValue) == 1)
               throw SocketException(0x01, "Timeout.", errno)
    }
}

一个子线程方法：

 void * Client::ClientStatesLoop(void * args)
 {
     char * clientIP = (char *)args;

     sem_t * semaphore;
     semaphore = sem_open(clientIP, O_CREAT, O_RDWR, 0);

     setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv, sizeof (struct timeval));

     ...

     while(1)
     {
          bufferInLen = recv(fd, bufferIn, BUF_SIZE, 0);  
          if((errno == EAGAIN) || (errno == EWOULDBLOCK))
          {
              sem_post(semaphore);
          }
     }
 }

这是GDB日志：

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
TCP Server v.2.0
[New Thread 0x7ffff6fd6700 (LWP 2425)]  // another thread
[New Thread 0x7ffff67d5700 (LWP 2426)]  // another thread
Połączono.
[New Thread 0x7ffff5fd4700 (LWP 2529)]  // parent thread
[New Thread 0x7ffff57d3700 (LWP 2530)]  // child thread

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff57d3700 (LWP 2530)]
0x00007ffff7bcb1c0 in sem_post () from /lib/x86_64-linux-gnu/libpthread.so.0

当我致电sem_post()时，这段错误的原因是什么？也许我应该使用除sem_open()以外的其他方法在子线程中使用名称semafore打开？

信号量，sem_post和分段错误

0 个答案: