keyfunc.c

select函数的应用实例。

#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main(void)
{
  int fdkey = -1;
  int fdkeypipe = -1;
  int ikeycode = 0;
  int result=0;
  char buf[2]={0,};
  fdkey = open("/dev/keypad",O_NONBLOCK,0);
  if(fdkey<0) 
  {
  	printf("Can't open keypad\n");
  	return -1;
  }
  fdkeypipe = open("/dev/keypipe",O_WRONLY);
  if(fdkeypipe<0)
  {
  	printf("Can't open keypipe\n");
  	return -1;
  }
  while(1)
  {
    result= read(fdkey,buf,sizeof(buf)); 
    if(result>0)
    {
    	if(buf[0]==0x01){
    		if(buf[1] == 0x0) ikeycode = 10;
    		else if(buf[1] == 0x1) ikeycode = 11;
    		else if(buf[1] == 0x2) ikeycode = 12;
    		else if(buf[1] == 0x3) ikeycode = 13;
    		else if(buf[1] == 0x4) ikeycode = 14;
    	}
    	else if(buf[0] == 0x02){
    		if(buf[1] == 0x0) ikeycode = 20;
    		else if(buf[1] == 0x1) ikeycode = 21;
    		else if(buf[1] == 0x2) ikeycode = 22;
    		else if(buf[1] == 0x3) ikeycode = 23;
    		else if(buf[1] == 0x4) ikeycode = 24;
    	}
    	else if(buf[0] == 0x04){
    		if(buf[1] == 0x0) ikeycode = 30;
    		else if(buf[1] == 0x1) ikeycode = 31;
    		else if(buf[1] == 0x2) ikeycode = 32;
    		else if(buf[1] == 0x3) ikeycode = 33;
    		else if(buf[1] == 0x4) ikeycode = 34;
    	}
    	else if(buf[0] == 0x08){
    		if(buf[1] == 0x0) ikeycode = 40;
    		else if(buf[1] == 0x1) ikeycode = 41;
    		else if(buf[1] == 0x2) ikeycode = 42;
    		else if(buf[1] == 0x3) ikeycode = 43;
    		else if(buf[1] == 0x4) ikeycode = 44;
    	}
    	else if(buf[0] == 0x10){
    		if(buf[1] == 0x0) ikeycode = 50;
    		else if(buf[1] == 0x1) ikeycode = 51;
    		else if(buf[1] == 0x2) ikeycode = 52;
    		else if(buf[1] == 0x3) ikeycode = 53;
    		else if(buf[1] == 0x4) ikeycode = 54;
    	}
    	else if(buf[0] == 0x20){
    		if(buf[1] == 0x0) ikeycode = 60;
    		else if(buf[1] == 0x1) ikeycode = 61;
    		else if(buf[1] == 0x2) ikeycode = 62;
    		else if(buf[1] == 0x3) ikeycode = 63;
    		else if(buf[1] == 0x4) ikeycode = 64;
    	}
    	//ckeycode = itoa(ikeycode);
    	//向管道写入键值供主程序读
    	write(fdkeypipe,&ikeycode,sizeof(ikeycode));
    	printf("in keyfun ckeycode = %d \n",ikeycode);	
    }
  }
  close(fdkey);
  close(fdkeypipe);
  return 0;
}