Recv不正确地返回零 [英] Recv returning zero incorrectly

问题描述

我有一个有趣的问题，

• 我将数据字节数据发送到我的服务器，从我的客户端和recv总是返回零。


• 我已验证该函数确实正在获取数据并将其放入char数组中。


• 我已验证客户端在recv（）返回零后仍然正确连接，并且仍然可以发送和接收数据到

这对我造成了问题。我需要总计了进来的字符以确定消息何时完成。有人可以解释什么可能导致recv（）命令以这种方式执行？

This creates a problem for me. I need to total up the chars coming in to determine when a message is completed. Can someone explain what could cause the recv() command to behave in this manner?

// clean the buffer of any previous received data
// by resetting all bytes to zero
ReadBufferClear();

// try to read some data, using the read buffer
if(this->Return_Value = recv(this->Socket_Filedescriptor,            
                    this->ReadBuffer_Data,
                    this->ReadBuffer_Size,
                    0) == -1)
{
    // returned -1, notify the server it needs
    // to remove this connections FD, and 
    // close this connection class entry;
    return -1;
}    

// print return value
fprintf(stdout,"%i\n",this->Return_Value);

// print out the bytes
for(int curPos  =0; curPos<this->ReadBuffer_Size; curPos++)
    fprintf(stdout,"%i\n",this->ReadBuffer_Data[curPos]);

输出如下所示：

0
0
1
-1
-1
-1
-2
-1
-1
0
0

0 0 1 -1 -1 -1 -2 -1 -1 0 0

推荐答案

您有优先问题。该行应为

You have a precedence problem. The line should be of the form

if ((this->ReturnValue = recv(..).)) == -1)

目前，您正在将recv（）的结果与-1进行比较，

At present you're comparing the result of recv() with -1 and storing the Boolean result of that comparison into ReturnValue.

所以recv（）根本不返回零。

So recv() isn't returning zero at all.

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