C选择（）超时标准输入单个字符（无ENTER） [英] C select() timeout STDIN single char (no ENTER)

问题描述

我希望能够使用选择（）从STDIN输入单个字符（无ENTER）上班。

I want to be able to use select() to work with entering a single char (no ENTER) from STDIN.

所以，当一个用户preSS一个键，选择（）应立即返回，而不是等待用户敲击回车键。

So, when a user press a single key, select() should return immediately, not waiting for the user to hit ENTER.

int main(void)
{
    fd_set rfds;
    struct timeval tv;
    int retval;

   /* Watch stdin (fd 0) to see when it has input. */
    FD_ZERO(&rfds);
    FD_SET(0, &rfds);

   /* Wait up to 2 seconds. */
    tv.tv_sec = 2;
    tv.tv_usec = 0;

   retval = select(1, &rfds, NULL, NULL, &tv);

   if (retval == -1)
        perror("select()");
    else if (retval)
        printf("Data is available now.\n");
    else
        printf("No data within five seconds.\n");

   exit(EXIT_SUCCESS);
}

这工作，但你必须按Enter键来完成。我只是想选择不等待用户打键和Enter键。

This works but you have to hit the ENTER key to finish. I just want the select not wait for the user to hit the key and ENTER.

感谢。

推荐答案

我相信，当钥匙进入终端，它的缓冲，直到你打回车，即只要程序而言，你没有输入任何东西。你可能想快速浏览一下在这个问题

I believe, when a key is entered into the terminal, it's buffered until you hit ENTER, i.e. as far as the program is concerned, you haven't entered anything. You might want to take a quick look at this question.

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