如何将套接字重置为阻塞模式（在我将其设置为非阻塞模式后）？

关于将套接字设置为非阻塞模式，我已经读过这个。

http://www.gnu.org/software/libc/manual/html_mono/libc.html#File-Status-Flags

这是我做的：

static void setnonblocking(int sock) { int opts; opts = fcntl(sock,F_GETFL); if (opts < 0) { perror("fcntl(F_GETFL)"); exit(EXIT_FAILURE); } opts = (opts | O_NONBLOCK); if (fcntl(sock,F_SETFL,opts) < 0) { perror("fcntl(F_SETFL)"); exit(EXIT_FAILURE); } return; } 

如何将套接字设置回阻止模式？ 我没有看到O_BLOCK标志？

谢谢。

Answer 1

你有没有尝试清除O_NONBLOCK标志？

 opts = opts & (~O_NONBLOCK) 

Answer 2

这是一个更具跨平台能力的解决方案：

 bool set_blocking_mode(const int &socket, bool is_blocking) { bool ret = true; #ifdef WIN32 /// @note windows sockets are created in blocking mode by default // currently on windows, there is no easy way to obtain the socket's current blocking mode since WSAIsBlocking was deprecated u_long non_blocking = is_blocking ? 0 : 1; ret = NO_ERROR == ioctlsocket(socket, FIONBIO, &non_blocking); #else const int flags = fcntl(socket, F_GETFL, 0); if ((flags & O_NONBLOCK) && !is_blocking) { info("set_blocking_mode(): socket was already in non-blocking mode"); return ret; } if (!(flags & O_NONBLOCK) && is_blocking) { info("set_blocking_mode(): socket was already in blocking mode"); return ret; } ret = 0 == fcntl(socket, F_SETFL, is_blocking ? flags ^ O_NONBLOCK : flags | O_NONBLOCK)); #endif return ret; } 

Answer 3

清除旗帜的另一种方法：

 opts ^= O_NONBLOCK; 

这将切换非阻塞标志，即如果当前启用则禁用非阻塞。