kbhit() for Linux

kbhit-linux.c

/**
 * MIT License
 *
 * Copyright (C) 2024 Carsten Janssen
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <stdio.h>
#include <termios.h>
#include <unistd.h>


/* returns non-zero if a key was hit */
int _kbhit()
{
    struct termios oldt, newt;
    int c;

    tcgetattr(STDIN_FILENO, &oldt);

    newt = oldt;
    newt.c_lflag &= ~(ICANON | ECHO);

    tcsetattr(STDIN_FILENO, TCSANOW, &newt);
    c = getchar();
    tcsetattr(STDIN_FILENO, TCSANOW, &oldt);

    if (c != EOF) {
        ungetc(c, stdin);
        return 1;
    }

    return 0;
}

int kbhit()
{
    return _kbhit();
}


int main()
{
    puts("Press any key to continue...");

    while (!kbhit()) {}

    puts("Done.");

    return 0;
}