Linux 标准输入struct input_event使用示例

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Input_event使用示例

下面贴出一段代码，该代码完成的功能是循环扫描设备列表，寻找你要打开的设备名，打开后非阻塞式的读取输入设备的输入内容。本设备的输入的设备名为”WCH.CN”，具体的设备名可以使用命令查看input列表里找到你的设备名，这里我也只是获取了按键的按下消息，从这部分消息中获取我的文本内容

#include <stdio.h>#include <stdlib.h>#include <pthread.h>#include <unistd.h>#include <string.h>#include <sys/types.h>#include <fcntl.h>#include <errno.h>#include <time.h>#include <linux/input.h>#define INPUT_NAME "WCH.CN"const char chr_table[129] = {[0] = '\0', [1] = '*', [2] = '1', [3] = '2', [4] = '3', [5] = '4', [6] = '5', [7] = '6', [8] = '7', [9] = '8',[10] = '9',[11] = '0', [12] = '-', [13] = '=', [14] = '\b', [15] = '\t', [16] = 'q', [17] = 'w', [18] = 'e', [19] = 'r',[20] = 't', [21] = 'y', [22] = 'u', [23] = 'i', [24] = 'o', [25] = 'p', [26] = '{', [27] = '}', [28] = '\n', [29] = '*',[30] = 'a', [31] = 's', [32] = 'd', [33] = 'f', [34] = 'g', [35] = 'h', [36] = 'j', [37] = 'k', [38] = 'l', [39] = ':',[40] = '"', [41] = '*', [42] = '*', [43] = '\\',[44] = 'z', [45] = 'x', [46] = 'c', [47] = 'v', [48] = 'b', [49] = 'n', [50] = 'm', [51] = ',', [52] = '.', [53] = '/', [54] = '*', [55] = '*', [56] = '*', [57] = ' ', [58] = '*', [59] = '*', [60] = '*', [61] = '*', [62] = '*', [63] = '*',[64] = '*', [65] = '*', [66] = '*', [67] = '*', [68] = '*', [69] = '*', [70] = '*', [71] = '*', [72] = '*', [73] = '*',[74] = '*', [75] = '*', [76] = '*', [77] = '*', [78] = '*', [79] = '*',[80] = '*', [81] = '*', [82] = '*', [83] = '*', [84] = '*',[85] = '*', [86] = '*', [87] = '*', [88] = '*', [89] = '*', [90] = '*', [91] = '*', [92] = '*', [93] = '*', [94] = '*', [95] = '*', [96] = '*', [97] = '*', [98] = '*', [99] = '*', [100] = '*', [101] = '*', [102] = '*', [103] = '*', [104] = '*', [105] = '*',[106] = '*', [107] = '*', [108] = '*',[109] = '*', [110] = '*',[111] = '*', [112] = '*', [113] = '*', [114] = '*', [115] = '*',[116] = '*', [117] = '*', [118] = '*', 119] = '*', [120] = '*',[121] = '*', [122] = '*', [123] = '*', [124] = '*', [125] = '*', [126] = '*', [127] = '*', [128] = '*'};static int open_input( const char *input_name ){    char name[64];    char buf[128];    int fd, flags;    int i = 0;    for (i = 0; i < 32; i++) {        sprintf(name, "/dev/input/event%d", i );        if( access( name, F_OK ) != 0 )            continue;        if ((fd = open(name, O_RDONLY, 0)) >= 0) {             ioctl(fd, EVIOCGNAME(sizeof(buf)), buf);             printf("name:%s \r\n", buf );             if( strstr( buf, input_name ) == NULL )             {                 close( fd );                 continue;             }            flags = fcntl(fd,F_GETFL,0);              flags |= O_NONBLOCK;              if( 0 != fcntl(fd,F_SETFL,flags) )                printf("fcntl failed!:%s \r\n", strerror( errno ));            printf("open for device:%s \r\n", name );            return fd;        }    }    return -1;}static int input_ready( int fd, int tout ){    fd_set  rfd_set;    struct  timeval tv, *ptv;    int nsel;    FD_ZERO( &rfd_set );    FD_SET( fd, &rfd_set );    if ( tout == -1 )    {           ptv = NULL;    }    else    {        tv.tv_sec = 0;        tv.tv_usec = tout * 1000;        ptv = &tv;    }    nsel = select( fd+1, &rfd_set, NULL, NULL, ptv );    if ( nsel > 0 && FD_ISSET( fd, &rfd_set ) )         return 1;    return 0;}static int read_input( int fd, char *buf , int maxsize ){    struct input_event event;    int rc;    int n = 0;    char *ptr = buf;    char ch;    int index;    int last_key;    do{        if( (rc = read(fd, &event, sizeof(event))) < 0)            return -1;        if( event.type == EV_KEY && event.value == 1 )        {            index = event.code & 0xff;            if( index  == 42 )            {                last_key = 42;                continue;            }            if( index < 128 )            {                ch = chr_table[index];                if( ch != 0 && ch != '*' )                {                    // shift key then a -> 'A'                    if( last_key == 42 )                        *ptr++ = ch - ( 'a' - 'A' );                    else                        *ptr++ = ch;                    last_key = 0;                    n++;                }            }        }    }while( input_ready( fd, 200 ) > 0 && n < maxsize );    *ptr = '\0';    return n;}int main( int argc, char *argv[] ){    int fd = -1;    int bRun = 1;    char buffer[256];    int len;    while( bRun )    {        if( fd < 0 )        {            //try to open input dev            fd  = open_input( INPUT_NAME );            if( fd < 0 )            {                printf("无输入设备可打开！\r\n");                sleep( 10 );                continue;            }            printf("设备打开成功，开始接收数据...\r\n");        }        if( input_ready( fd, 200 ) > 0 )        {            len = read_input( fd, buffer, sizeof( buffer ));            if( len < 0 )            {                printf("设备已断开！，关闭！\r\n");                fd = -1;                continue;            }        }        printf("READ:%s \r\n", buffer);    }}

下面附上struct input_event结构的使用代码

/*  * 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;  }

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