_kbhit() for linux

传送门：http://cboard.cprogramming.com/c-programming/63166-kbhit-linux.html

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

int kbhit(void)
{
  struct termios oldt, newt;
  int ch;
  int oldf;

  tcgetattr(STDIN_FILENO, &oldt);
  newt = oldt;
  newt.c_lflag &= ~(ICANON | ECHO);
  tcsetattr(STDIN_FILENO, TCSANOW, &newt);
  oldf = fcntl(STDIN_FILENO, F_GETFL, );
  fcntl(STDIN_FILENO, F_SETFL, oldf | O_NONBLOCK);

  ch = getchar();

  tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
  fcntl(STDIN_FILENO, F_SETFL, oldf);

  if(ch != EOF)
  {
    ungetc(ch, stdin);
    return ;
  }

  return ;
}

main( int argc, char** argv )
{
    char *input = argv[];
    int nomor = argc;
    pid_t pid = ;
    /* set stuff up */
    /* accept command line args */

    pid = fork();
    if( pid ==  ){
        /* this is the "background" process.  Execute process loop here */
        int x=;
        while()
        {
            if(kbhit())
              printf("you hit keyboard");
        }
    }
    else {
        /* "foreground" process exits */
        exit();
    }
}

具体含义，有的解释是等待键盘输入；但此处用意为在 ios下使用while( !kbhit()) 控制openal的音效的循环播放.