VxWorks中串口fd_set操作实现读写监听

/*利用VxWorks的些许POSIX特性，
使用fd文件描述符来接收数据、
用select来提供超时，
*/
/*下面代码照例是单字节获取串口数据，
提供毫秒为单位的超时机制。
*/

view plaincopy to clipboardprint?BOOLEAN UARTGet(      OUT PBYTE c,      IN ULONG Timeout)    // unit in ms  {      int                n;      int                max_fd;      fd_set            input;      struct timeval    timeout;        // Initialize the input      FD_ZERO(&input);      FD_SET(STD_IN, &input);      max_fd = STD_IN + 1;        // Initialize the timeout structure      timeout.tv_sec = 0;      timeout.tv_usec = Timeout * 1000;        // Do the select      n = select(max_fd, &input, NULL, NULL, &timeout);        // see it there was an error      if(n < 0)          //perror(“select failed”);          n = 0;      else if(n == 0)          //puts(“TIMEOUT”);          n = 0;      else      {          // we have input          n = 0;          if(FD_ISSET(STD_IN, &input))              n = read(STD_IN, (char *)c, 1);      }      return n;  }    VOID UARTPut(IN BYTE c)  {      // "/tyCo/0"      write(STD_OUT, (char *)&c, 1);  }  BOOLEAN UARTGet(
    OUT PBYTE c,
    IN ULONG Timeout)    // unit in ms
{
    int                n;
    int                max_fd;
    fd_set            input;
    struct timeval    timeout;

    // Initialize the input
    FD_ZERO(&input);
    FD_SET(STD_IN, &input);
    max_fd = STD_IN + 1;

    // Initialize the timeout structure
    timeout.tv_sec = 0;
    timeout.tv_usec = Timeout * 1000;

    // Do the select
    n = select(max_fd, &input, NULL, NULL, &timeout);

    // see it there was an error