Date:	Wed, 19 Feb 2003 08:26:44 +0200
From:	Zaretskii Eli <ezaretski AT elta DOT co DOT il>
Subject:	RE: COM1: always non-blocking?
To:	Keith Doyle <kdd21 AT hotmail DOT com>, djgpp AT delorie DOT com
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> From: Keith Doyle [mailto:kdd21 AT hotmail DOT com] 
> Sent: Tuesday, February 18, 2003 10:01 PM
> 
> So, I gave up on dzcomm, bcserio,pmcom, etc..  I then thought for a
> moment, that under a DOS window you can do something as simple as
> "echo 'hello' >COM1" so why not just trying to do an open on COM1:.

You don't need to do that, actually: file descriptor 3 is already
preconnected to the COM1 port, and the stdaux FILE object is open on
that descriptor.  Just use them.

> Well, it worked pretty good.  The only gotcha seems to be that read
> appears to always be NONBLOCKING

Please explain what you mean by this.  DJGPP generally doesn't support
non-blocking I/O (since it requires a multiprocessing OS).

> I tried using fcntl, ioctl, and tcgetattr, but none of these seemed to
> do anything useful (though for fcntl and tcgetattr, I just tried to
> GET the current info, rather than set anything, but because it always
> seemed to return 0 for everything, I figured this stuff isn't
> connected...).

Fcntl, ioctl, and termios don't really support COMx ports in the DJGPP
implementation, since DOS system calls don't. Sorry.


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