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recv() Windows 套接字需要无限时间 - 如何超时？

发布于 2024-11-25 01:15:50 字数 101 浏览 0 评论 0原文

我使用文件描述符来查找可读套接字并继续读取。由于某些原因，线路上没有数据的套接字会继续读取并且永远不会返回。有没有办法让我在超时后退出接收？

我正在使用winsock库..

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新雨望断虹 2024-12-02 01:15:50

http://tangentsoft.net/wskfaq/newbie.html#timeout

2.15 - 如何更改超时Winsock 函数？

一些阻塞Winsock 函数（例如connect()）中嵌入了超时。这背后的理论是，只有堆栈拥有设置适当超时所需的所有信息。然而，有些人发现堆栈使用的值对于他们的应用程序来说太长了；可以是一分钟或更长时间。

您可以使用 SO_SNDTIMEO 和 SO_RCVTIMEO setsockopt() 选项调整 send() 和 receive() 超时。。

对于其他 Winsock 函数，最好的解决方案是完全避免阻塞套接字。所有非阻塞套接字方法都为您提供了构建自定义超时的方法：

Non-blocking sockets with select() – The fifth parameter to the select() function is a timeout value.

Asynchronous sockets – Use the Windows API SetTimer().

Event objects – WSAWaitForMultipleEvents() has a timeout parameter.

Waitable Timers – Call CreateWaitableTimers() to make a waitable timer, which you can then pass to a function like WSAEventSelect() along with your sockets: if none of the sockets is signalled before the timer goes off, the blocking function will return anyway.

请注意，使用异步和非阻塞套接字，您可以完全避免处理超时。即使 Winsock 很忙，您的程序也会继续工作。因此，您可以让用户自行取消耗时过长的操作，或者只是让 Winsock 的自然超时到期，而不是在代码中接管此功能。

http://tangentsoft.net/wskfaq/newbie.html#timeout

2.15 - How can I change the timeout for a Winsock function?

Some of the blocking Winsock functions (e.g. connect()) have a timeout embedded into them. The theory behind this is that only the stack has all the information necessary to set a proper timeout. Yet, some people find that the value the stack uses is too long for their application; it can be a minute or longer.

You can adjust the send() and recv() timeouts with the SO_SNDTIMEO and SO_RCVTIMEO setsockopt() options. .

For other Winsock functions, the best solution is to avoid blocking sockets altogether. All of the non-blocking socket methods provide ways for you to build custom timeouts:

Non-blocking sockets with select() – The fifth parameter to the select() function is a timeout value.

Asynchronous sockets – Use the Windows API SetTimer().

Event objects – WSAWaitForMultipleEvents() has a timeout parameter.

Waitable Timers – Call CreateWaitableTimers() to make a waitable timer, which you can then pass to a function like WSAEventSelect() along with your sockets: if none of the sockets is signalled before the timer goes off, the blocking function will return anyway.

Note that with asynchronous and non-blocking sockets, you may be able to avoid handling timeouts altogether. Your program continues working even while Winsock is busy. So, you can leave it up to the user to cancel an operation that’s taking too long, or just let Winsock’s natural timeout expire rather than taking over this functionality in your code.

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玩心态 2024-12-02 01:15:50

你的问题出在你尝试填充缓冲区的 while 循环中
只需放置一个 if 语句来检查每个块的最后一个索引是否为 '\0'
然后打破你的 while 循环

do {
    len = rcv(s,buf,BUF_LEN,0);
    for (int i = 0; i <= len; ++i) {
        if (buf[i] >= 32 || buf[i] == '\n' || buf[i] == '\r') { //only write valid chars
            result += buf[i]; //final string
        }
    }
    if (buf[len] == '\0') { //buf[len] is the last position in the received chanks 
        break;
    }
} while (inner_result > 0);

your problem is in the while loop that you try to fill buffer
just put an if statement that check last index of every chunks for '\0'
then break your while loop

do {
    len = rcv(s,buf,BUF_LEN,0);
    for (int i = 0; i <= len; ++i) {
        if (buf[i] >= 32 || buf[i] == '\n' || buf[i] == '\r') { //only write valid chars
            result += buf[i]; //final string
        }
    }
    if (buf[len] == '\0') { //buf[len] is the last position in the received chanks 
        break;
    }
} while (inner_result > 0);

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