c - Errno 35 (EAGAIN) 在 recv 调用时返回

Question

我有一个等待 recv 的套接字，然后在接收到数据后，向前发送数据进行处理。然而，然后它再次进行 recv，这次它没有收到任何返回 -1，当打印 errno 时它打印 35(即 EAGAIN)。

这只发生在 MAC OS Lion 操作系统上，对于其他操作系统，它运行得很好

do{
 rc = recv(i, buffer, sizeof(buffer), 0);
 if (rc < 0){
      printf("err code %d", errno); 
 }
 if(rc == 0){ 
      //Code for processing the data in buffer 
      break; 
 } 
      ....
}while(1);

编辑:更正缩进和错误

Answer 1

您要么将套接字设置为非阻塞模式，要么启用接收超时。这是来自 recv(2)在 Mac 上:

The calls fail if:

[EAGAIN] The socket is marked non-blocking, and the receive operation would block, or a receive timeout had been set, and the timeout expired before data were received.

编辑0:

嗯，抱歉再次引用。这次来自intro(2) :

11 EDEADLK Resource deadlock avoided. An attempt was made to lock a system resource that would have resulted in a deadlock situation.

...

35 EAGAIN Resource temporarily unavailable. This is a temporary condition and later calls to the same routine may complete normally.

只需使用 strerror(3)找出实际问题。