有一些应用程序，用x11库制作，测试了ubuntu。它采用简单的键盘输入并输出相应的值。如果应用程序窗口（Ubuntu终端）当前处于打开状态，则可以正常工作
linux-kbhit.h

#define     ESC     "\033"
#define     UP      "\033[A"
#define     DOWN    "\033[B"
#define     LEFT    "\033[D"
#define     RIGHT   "\033[C"
#define     A   "a"

void term_setup(void (*sighandler)(int));
void term_restore();
bool kbhit();
bool keydown(const char* key);

字符串
linux-kbhit.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <unistd.h>
#include <poll.h>
#include <signal.h>
#include <termios.h>
#include <sys/ioctl.h>

static struct termios oldtio;
static struct termios curtio;

void term_setup(void (*sighandler)(int)){
    struct sigaction sa;

    /* Save stdin terminal attributes */
    tcgetattr(0, &oldtio);

    if(sighandler){
    /* Make sure we exit cleanly */
        memset(&sa, 0, sizeof(struct sigaction));
        sa.sa_handler = sighandler;
        sigaction(SIGINT, &sa, NULL);
        sigaction(SIGQUIT, &sa, NULL);
        sigaction(SIGTERM, &sa, NULL);
    }

    /* This is needed to be able to tcsetattr() after a hangup (Ctrl-C)
     * see tcsetattr() on POSIX
     */
    memset(&sa, 0, sizeof(struct sigaction));
    sa.sa_handler = SIG_IGN;
    sigaction(SIGTTOU, &sa, NULL);

    /* Set non-canonical no-echo for stdin */
    tcgetattr(0, &curtio);
    curtio.c_lflag &= ~(ICANON | ECHO);
    tcsetattr(0, TCSANOW, &curtio);
}

void term_restore(){
    /* restore terminal attributes */
    tcsetattr(0, TCSANOW, &oldtio);
}

static char get[4]= {0};
bool kbhit(){
    struct pollfd pfds[1];
    int ret;
    memset(get, 0, sizeof(char) * 4);

    /* See if there is data available */
    pfds[0].fd = 0;
    pfds[0].events = POLLIN;
    ret = poll(pfds, 1, 0);

    /* Consume data */
    if (ret > 0) {
        read(0, get, 3);
        return strlen(get) > 0;
    }
    return false;
}

bool keydown(const char* key){
    return !strcmp(get, key);
}

型
它完美地适用于活动应用程序的键盘输入，但应用程序的目的是获取所有OS键输入并解释它以供进一步使用
main.c

#include "linux-kbhit.h"
#include "stdio.h"
#include <signal.h>

static sig_atomic_t end = 0;
static void sighandler(int signo)
{
    end = 1;
    printf("good beye!\n");
}

int main()
{
    term_setup(sighandler);

    while (!end) {
        if (kbhit()) {
            if (keydown(ESC))
                printf("This is \"ESC\" button!\n");
            if (keydown(UP))
                printf("This is \"UP\" button!\n");
            if (keydown(DOWN))
                printf("This is \"DOWN\" button!\n");
            if (keydown(LEFT))
                printf("This is \"LEFT\" button!\n");
            if (keydown(RIGHT))
                printf("This is \"RIGHT\" button!\n");
            if (keydown(A))
                printf("This is \"A\" button!\n");
        }
    }

    term_restore();

    return 0;
}

型
我需要从操作系统（Ubuntu）中的任何应用程序获取密钥我应该如何修改代码？