Re: forkpty with streams

[Andrew Barton <andrevv@users.sourceforge.net>]

On Fri, 2003-07-25 at 18:46, Matti Aarnio wrote:

> dup() helps you to have two fd:s,  fdopen() for both, one with "w",
> other "r".   Things should not need that dup() actually.
> Also fcntl() the fd's to be non-blocking.
> 
> Actually I am always nervous with stdio streams in places
> where I want to use non-blocking file handles, and carefull
> read()ing and write()ng along with select()s to handle
> non-stagnation of this type of communications.
> 

In my program, the standard input is filtered through a lex scanner
whose output file is the pty. So it does indeed need to be a stream.
Since I'm using flex, I won't have much control over the writing
process. When will it be necessary to read from the pty, to prevent a
deadlock? After each character the user types?

I might use SIGIO to read from the pty, but I have the 2.4 kernel that
doesn't support SIGIO on pipes and FIFOs. I assume ptys have the same
problem.