Subject: Q: about t_hwiflow
To: None <tech-kern@NetBSD.ORG>
From: Bill Studenmund <>
List: tech-kern
Date: 01/29/1996 17:54:17
Hello again.

I'm not sure if this is the right venue for this question, so please
re-direct if needed. :-)

I have a question about the t_hwiflow routine in the tty system.
As I understand it, it is called to raise or lower the hardware
handshake lines. It gets passed the tty, and a flag saying which
way to go.

My question is whether or not I understand its return value. It
returns !=0 if it succeded, no? And it returns 0 if it failed?

I ask as the mac68k port has only one RS-232 output which is usually
used for DTR (hanging up the modem), but two inputs, CTS & DCD.
When modeming, CTS tells us when to shut up, DCD says if we have
carrier, and DTR lets us hang up the phone.

When we're in crtscts, we don't have an output flow line, so
t_hwiflow should just fail. ?