c++ - 强制 recv (Windows C++) 函数阻塞，直到读取 N 个字节

Question

我正在使用 this客户端-服务器架构的代码。代码可以轻松运行，没有任何问题。然而，TCP 将大数据包分成多个小数据包。问题来自 recv 函数。我是 Windows 编程的新手，想知道是否有类似 read 函数的东西会阻塞，直到它从客户端套接字读取所有 N 个字节(就像在 Linux 中，当你想从客户端套接字 fd 读取时一样)。有什么想法吗？

Answer 1

Windows recv documentation列出一个 MSG_WAITALL 标志，它将使调用等待直到给定缓冲区完全填满:

MSG_WAITALL The receive request will complete only when one of the following events occurs:

• The buffer supplied by the caller is completely full.
• The connection has been closed.
• The request has been canceled or an error occurred.

例子:

iResult = recv(ConnectSocket, recvbuf, recvbuflen, MSG_WAITALL);