Syntax:
value = kbhit()

value = kbhit (stream)



Parameters:
stream is the stream id assigned to an available RS232 port.  If the stream parameter is not included, the function uses the primary stream used by getc().



Returns:
0 (or FALSE) if getc() will need to wait for a character to come in, 1 (or TRUE) if a character is ready for getc()



Function:
If the RS232 is under software control this function returns TRUE if the start bit of a character is being sent on the RS232 RCV pin.  If the RS232 is hardware this function returns TRUE if a character has been received and is waiting in the hardware buffer for getc() to read.  This function may be used to poll for data without stopping and waiting for the data to appear.  Note that in the case of software RS232 this function should be called at least 10 times the bit rate to ensure incoming data is not lost.



Availability:
All devices.



Requires:
#use rs232



Examples:
char timed_getc() {
   long timeout;

   timeout_error=FALSE;
   timeout=0;

   while(!kbhit()&&(++timeout<50000)) // 1/2
                                    // second

          delay_us(10);
   if(kbhit())
          return(getc());
   else {
          timeout_error=TRUE;
          return(0);
   }

}

while(!kbhit());
somevar = getc();