joystick.c

来自「在linux下多媒体开发实例linux下多媒体开发」· C语言 代码 · 共 58 行

/*
 * joystick.c
 * Example program for joystick driver. Returns status of first
 * joystick. Requires kernel joystick driver.
 */

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <linux/joystick.h>

int main()
{
  int fd, status;
  struct JS_DATA_TYPE js;
  struct JS_DATA_SAVE_TYPE jsd;

  /* open device file */
  status = fd = open("/dev/js0", O_RDONLY);
  if (status < 0) {
    perror("open of /dev/js0 failed");
    exit(1);
  }

  /* display current settings */
  status = ioctl(fd, JS_GET_ALL, &jsd);
  if (status == -1) {
    perror("error from ioctl");
    exit(1);
  }
  printf(
	 "timeout: %d  busy: %d  expire time: %ld  time limit: %ld\n"
	 "buttons: %d  x: %d  y: %d  x corr: %d  y corr: %d\n"
	 "Current joystick settings: (interrupt to exit)\n",
	 jsd.JS_TIMEOUT, jsd.BUSY, jsd.JS_EXPIRETIME,
	 jsd.JS_TIMELIMIT, jsd.JS_SAVE.buttons,
	 jsd.JS_SAVE.x, jsd.JS_SAVE.y,
	 jsd.JS_CORR.x, jsd.JS_CORR.y);

  while (1) {
    status = read(fd, &js, JS_RETURN);
    if (status != JS_RETURN) {
      perror("error reading /dev/js0");
      exit(1);
    }
    printf("button 0: %s  button 1: %s  X axis: %4d  Y axis: %4d\r",
	    (js.buttons & 0x01) ? "on " : "off",
	    (js.buttons & 0x02) ? "on " : "off",
	    js.x,
	    js.y);
    fflush(stdout); /* make sure line is output */
    usleep(100); /* don't run too fast */
  }
  exit(0);
}