监听键盘

/*keyboardview.c*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <linux/input.h>
#include <sys/stat.h>
#include <fcntl.h>
int main ()
{
    int keys_fd;
    int pipes[2];
    struct input_event t;
    char buf[100];
    int pid,pid1;
    int nread;
    int key_code;
    if(pipe(pipes) < 0)
    {
        printf("%s
","pipes error!" );
        exit(EXIT_FAILURE);
    }
    pid = fork();
    if(pid < 0 )
    {
        printf("%s
","fork() function error!" );;
        exit(EXIT_FAILURE);
    }
    else if(pid == 0)
    {
        keys_fd = open ("/dev/input/event4", O_RDONLY);
        if (keys_fd <= 0)
        {
            printf ("open /dev/input/event4 device error!
");
        }
        close(pipes[0]);
        while (1)
        {
            if (read (keys_fd, &t, sizeof (t)) == sizeof (t))
            {
                if (t.type == EV_KEY)
                {
                    if ( t.value == 0)
                    {
                        printf ("key %d 
", t.code);
                        //sprintf(buf,"key %d 
", t.code);
                        key_code = t.code;
                        write(pipes[1],&key_code,sizeof(key_code));
                        if(t.code==KEY_ESC)
                            break;
                    }
                }
            }
        }
        close (keys_fd);
        close(pipes[1]);
        exit(EXIT_SUCCESS);
    }
    else
    {
        pid1 = fork();
        if(pid1 < 0 )
        {
            printf("%s
"," fork function error" );
            exit(EXIT_FAILURE);
        }
        if(pid1 == 0)
        {
            FILE * fp;
            close(pipes[1]);
            //int writefd;
            fp = fopen("data.out","w+");
            //writefd = open("data.out", O_WRONLY | O_CREAT);
            while(1)
            {
                read(pipes[0],&key_code,sizeof(key_code));
                //write(writefd,&key_code,sizeof(key_code));
                fprintf( fp,"%d    ",key_code);
                if(key_code == 1)
                    break;
            }
            close(pipes[0]);
            exit(EXIT_SUCCESS);
        }
        else
        {
            exit(EXIT_SUCCESS);
        }         
    } 
    return 0;
}