Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!egrunix!schemers
From: schemers@egrunix.UUCP (Roland Schemers)
Newsgroups: comp.sys.amiga
Subject: Re: Relying on ARP (was Re: My AmigaDOS 1.4 wishlist (one among thousands!))
Summary: popen!
Keywords: popen, pclose, unix, arp
Message-ID: <126@egrunix.UUCP>
Date: 4 Aug 89 16:09:07 GMT
References: <12878@well.UUCP> <26758@agate.BERKELEY.EDU> <20904@cup.portal.com> <26915@agate.BERKELEY.EDU> <11107@polya.Stanford.EDU>
Reply-To: schemers@unix.secs.oakland.edu.UUCP (Roland Schemers)
Followup-To: 32202
Distribution: na
Organization: Oakland University, Rochester, MI
Lines: 21


> I've always wanted to be able to fopen("|lpr", "w"), for instance, to
> spool things automatically, or anything else with pipes.  Why hasn't
> any operating system (that I know of) allowed file names to also specify
> new processes?  I mean, I can open `par:' or `ser:' or even `speak:'.
> Just a thought.

Since no one else has posted an answer (I'm sure they will), I guess 
I'll do the honers. Unix has EXACTLY what you want. The system call is called
popen! (Stands for Pipe? Process? open). Is has the following syntax:

FILE *lpr_file;

lpr_file = popen("lpr","w");

Then you can do all the normal file commands with it (fprint, etc...), and
when you are do, just issue the pclose(lpr_file) call. I remember seeing
a posting on swan.ulowell.edu, which has the popen call as written for the
Amiga, although I do beleive you need Arp and a PIP: device to use it.

roland (no cute sig) schemers