getc help needed

[Conor P. Cahill]

In article <2056 at leah.Albany.Edu>, tmm33 at leah.Albany.Edu (Terry McCoy) writes:
> I have looked at the getc function in the stdio.h header file and noticed that
> it calls a function _filbuf.  I think that this function is located within the
> kernal and controls the pointers, flags and the counter within the structure

Nope.  _filbuf is a stdio library function that eventually uses read(2) to 
fill the buffer.

> FILE.  Any information on how this function works or how I could tell if data
> has arrived at the serial port without waiting would be helpful.

Since you are reading data off of the serial port you should use the 
following type of code:

	#include <fcntl.h>

	fd = open(TTY_PORT,O_RDWR+O_NDELAY....)

	if( (cnt=read(fd,buffer,512)) > 0 )
		/* process the data */
	else if( cnt == -1 )
		/* handle read failure */
	/* else cnt = 0 (no data available) */

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