Subject: Re: Serial port questions
To: Bruce Martin <BruceM@cat.co.za>
From: David Brownlee <abs@anim.dreamworks.com>
List: netbsd-help
Date: 07/25/1999 12:24:52
On Sat, 24 Jul 1999, Bruce Martin wrote:

> 3 Questions:
> 
> - I want to get a character from the receive buffer, but there may not
> always be one: how do I check if it is empty first, or timeout after
> trying to read it for a while?
> 
	You can use something like 
	fcntl(fd,F_SETFL,fcntl(fd,F_GETFL)|O_NONBLOCK)
	to set the filedescriptor to be non blocking, then use read(...)
	to read the data.
	To check if data is present use poll(1) or select(1).

> - How do I change the DTR line state?
> 
	The answer to that is probably somewhere under termios(4)
	(man 4 termios)

> - How do I change the depth of the FIFO required to cause an interrupt?

	That would almost certainly be in the kernel chip driver

		David/absolute

	 -=-  "That which does not kill us, makes us stranger"  -=-