linux下input event事件，可以用后台截取键盘按下的键值，后台截取数据.....input.h

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linux下input event事件，可以用后台截取键盘按下的键值，后台截取数据.....input.h

时间 2014-12-04 12:00:50 CSDN博客 原文  http://blog.csdn.net/chenxun_2010/article/details/41722119

如何读取Linux键值，输入子系统，key，dev/input/event，dev/event，C语言键盘？

这里先上一段代码，自己拿到linux系统运行就可以，注意代码中 keys_fd = open("/dev/input/event2", O_RDONLY);      这里去你的/dev/input/event2的event事件，去查看你的键盘事件是那一个，如果是event3那么你改成event3好了。这里给 一个命令你去查看  cat  / proc /bus/usb/devices

http://www.jb51.net/LINUXjishu/30628.html 如果还是查找不到请看这个链接。   在一个终端中运行下面的代码，再打开另开一个中按下按键，然后查看第一个终端中输出的信息你就知道是怎么回事了，哈哈，是不是获取你按下键盘的键值 了？？？  oh yeah！  建议再去查看一下linux下input 子系统的介绍和查看一下input.h文件，网上一大堆，你一查你就知道了是怎么回事了。

#include <stdio.h>  
#include <stdlib.h>  
#include <unistd.h>  
#include <string.h>  
#include <sys/types.h>  
#include <fcntl.h>  
#include <errno.h>  
#include <time.h>  
#include <linux/input.h>  

int main()
{
  int keys_fd;
  char ret[2];
  struct input_event t;
  keys_fd = open("/dev/input/event2", O_RDONLY);
  if (keys_fd <= 0)
  {
    printf("open /dev/input/event2 device error!\n");
    return 0;
  }

  while (1)
  {
    if (read(keys_fd, &t, sizeof (t)) == sizeof (t))
    {
      if (t.type == EV_KEY)
      if (t.value == 0 || t.value == 1)
      {
        printf("key %d %s\n", t.code, (t.value) ? "Pressed" : "Released");
        if (t.code == KEY_ESC)
          break;
      }
    }
  }

  close(keys_fd);

  return 0;
}

好了，这里给出一个重量级的代码，比上面的更完整.,自己拿去运行好好分析一下就知道怎么回事了....

/*
* Copyright 2002 Red Hat Inc., Durham, North Carolina.
*
* All Rights Reserved.
*
* 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 on 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 (including the
* next paragraph) 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
* NON-INFRINGEMENT.  IN NO EVENT SHALL RED HAT AND/OR THEIR SUPPLIERS
* 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.
*
* This is a simple test program that reads from /dev/input/event*,
* decoding events into a human readable form.
*/

/*
* Authors:
*   Rickard E. (Rik) Faith <faith@redhat.com>
*
*/

#include <stdio.h>  
#include <stdlib.h>  
#include <unistd.h>  
#include <string.h>  
#include <sys/types.h>  
#include <fcntl.h>  
#include <errno.h>  
#include <time.h>  
#include <linux/input.h>  

struct input_event event;

int main(int argc, char **argv)
{
  char          name[64];           /* RATS: Use ok, but could be better */
  char          buf[256] = { 0, };  /* RATS: Use ok */
  unsigned char mask[EV_MAX / 8 + 1]; /* RATS: Use ok */
  int           version;
  int           fd = 0;
  int           rc;
  int           i, j;
  char          *tmp;

#define test_bit(bit) (mask[(bit)/8] & (1 << ((bit)%8)))  

  for (i = 0; i < 32; i++) {
    sprintf(name, "/dev/input/event%d", i);
    if ((fd = open(name, O_RDONLY, 0)) >= 0) {
      ioctl(fd, EVIOCGVERSION, &version);
      ioctl(fd, EVIOCGNAME(sizeof(buf)), buf);
      ioctl(fd, EVIOCGBIT(0, sizeof(mask)), mask);
      printf("%s\n", name);
      printf("    evdev version: %d.%d.%d\n",
        version >> 16, (version >> 8) & 0xff, version & 0xff);
      printf("    name: %s\n", buf);
      printf("    features:");
      for (j = 0; j < EV_MAX; j++) {
        if (test_bit(j)) {
          const char *type = "unknown";
          switch (j) {
          case EV_KEY: type = "keys/buttons"; break;
          case EV_REL: type = "relative";     break;
          case EV_ABS: type = "absolute";     break;
          case EV_MSC: type = "reserved";     break;
          case EV_LED: type = "leds";         break;
          case EV_SND: type = "sound";        break;
          case EV_REP: type = "repeat";       break;
          case EV_FF:  type = "feedback";     break;
          }
          printf(" %s", type);
        }
      }
      printf("\n");
      close(fd);
    }
  }

  if (argc > 1) {
    sprintf(name, "/dev/input/event%d", atoi(argv[1]));
    if ((fd = open(name, O_RDWR, 0)) >= 0) {
      printf("%s: open, fd = %d\n", name, fd);
      for (i = 0; i < LED_MAX; i++) {
        event.time.tv_sec = time(0);
        event.time.tv_usec = 0;
        event.type = EV_LED;
        event.code = i;
        event.value = 0;
        write(fd, &event, sizeof(event));
      }

      while ((rc = read(fd, &event, sizeof(event))) > 0) {
        printf("%-24.24s.%06lu type 0x%04x; code 0x%04x;"
          " value 0x%08x; ",
          ctime(&event.time.tv_sec),
          event.time.tv_usec,
          event.type, event.code, event.value);
        switch (event.type) {
        case EV_KEY:
          if (event.code > BTN_MISC) {
            printf("Button %d %s",
              event.code & 0xff,
              event.value ? "press" : "release");
          }
          else {
            printf("Key %d (0x%x) %s",
              event.code & 0xff,
              event.code & 0xff,
              event.value ? "press" : "release");
          }
          break;
        case EV_REL:
          switch (event.code) {
          case REL_X:      tmp = "X";       break;
          case REL_Y:      tmp = "Y";       break;
          case REL_HWHEEL: tmp = "HWHEEL";  break;
          case REL_DIAL:   tmp = "DIAL";    break;
          case REL_WHEEL:  tmp = "WHEEL";   break;
          case REL_MISC:   tmp = "MISC";    break;
          default:         tmp = "UNKNOWN"; break;
          }
          printf("Relative %s %d", tmp, event.value);
          break;
        case EV_ABS:
          switch (event.code) {
          case ABS_X:        tmp = "X";        break;
          case ABS_Y:        tmp = "Y";        break;
          case ABS_Z:        tmp = "Z";        break;
          case ABS_RX:       tmp = "RX";       break;
          case ABS_RY:       tmp = "RY";       break;
          case ABS_RZ:       tmp = "RZ";       break;
          case ABS_THROTTLE: tmp = "THROTTLE"; break;
          case ABS_RUDDER:   tmp = "RUDDER";   break;
          case ABS_WHEEL:    tmp = "WHEEL";    break;
          case ABS_GAS:      tmp = "GAS";      break;
          case ABS_BRAKE:    tmp = "BRAKE";    break;
          case ABS_HAT0X:    tmp = "HAT0X";    break;
          case ABS_HAT0Y:    tmp = "HAT0Y";    break;
          case ABS_HAT1X:    tmp = "HAT1X";    break;
          case ABS_HAT1Y:    tmp = "HAT1Y";    break;
          case ABS_HAT2X:    tmp = "HAT2X";    break;
          case ABS_HAT2Y:    tmp = "HAT2Y";    break;
          case ABS_HAT3X:    tmp = "HAT3X";    break;
          case ABS_HAT3Y:    tmp = "HAT3Y";    break;
          case ABS_PRESSURE: tmp = "PRESSURE"; break;
          case ABS_DISTANCE: tmp = "DISTANCE"; break;
          case ABS_TILT_X:   tmp = "TILT_X";   break;
          case ABS_TILT_Y:   tmp = "TILT_Y";   break;
          case ABS_MISC:     tmp = "MISC";     break;
          default:           tmp = "UNKNOWN";  break;
          }
          printf("Absolute %s %d", tmp, event.value);
          break;
        case EV_MSC: printf("Misc"); break;
        case EV_LED: printf("Led");  break;
        case EV_SND: printf("Snd");  break;
        case EV_REP: printf("Rep");  break;
        case EV_FF:  printf("FF");   break;
          break;
        }
        printf("\n");
      }
      printf("rc = %d, (%s)\n", rc, strerror(errno));
      close(fd);
    }
  }
  return 0;
}