15

我已阅读有关将套接字设置为非阻塞模式的内容。

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

这是我所做的：

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塞模式？我没有看到 O_BLOCK 标志？

谢谢你。

4

3 回答 3

16

您是否尝试清除 O_NONBLOCK 标志？

opts = opts & (~O_NONBLOCK)
于 2010-01-27T19:53:14.180 回答
6

这是一个更具跨平台能力的解决方案：

bool set_blocking_mode(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;
}
于 2015-10-12T18:45:53.537 回答
0

清除标志的另一种方法：

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。

于 2010-01-27T23:00:19.180 回答