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From: car@public.BTR.COM (Carlos Rimola-Sarti  car@btr.com)
Newsgroups: comp.os.os2.programmer
Subject: Porting from Unix to OS/2
Message-ID: <3126@public.BTR.COM>
Date: 19 Jun 91 22:47:05 GMT
Organization: Communications Solutions, Inc. (CSI)  Mountain View, California
Lines: 42

I am in the process of porting a large piece of code from Unix to OS/2
and I was wondering if anyone has had similar experiences to mine.

For background, the code that I am porting consists of a device driver, 
a daemon and an application.  They all talk to each other via named
pipes and/or device open/close/read/write/ioctl. 

One of the first things that I had to decide was what to do about 
the Unix fork() call.  The application makes use of fork to spawn off
background processes.  The "right" thing to do is probably to redesign
the app to use threads instead of fork().  However, the app will be
thrown away and I only needed to verify that the other pieces are
working.  Because of this, I thought that moving the application to
OS/2 would be made a lot easier if I could emulate fork.  

After thinking about it I decided that fork() could not be easily emulated
using threads.  A forked process inherits its own copy of the data
segment (with current values) and also inherits other context like
installed signal handlers (which this application makes use of).  All
of these characteristics convinced me that it would be easier to
simulate fork() by spawning an OS/2 process.  I have been able to
come up with a scheme (hack?) that works but I still have a few 
questions:

1) Has anyone had a similar experience?  what did you do?

2) Is there a way in OS/2 to start a second process without having
to specify an executable file that the OS will have to load from disk?
In other words,  why can't I just tell the OS where the code is?

3) Is there a clean way for a process to determine that IT is the
first process in a session?  i.e., one that was not spawned off by
another process in the same session.

4) I would also like to hear about any other things to watch out for
in porting code from one OS to the other and general comments on
what others may have experienced.

+---------------------------------------+-----------------------------------+
| Carlos Rimola-Sarti			|		email: car@btr.com  |
| Communications Solutions, Inc.	|		phone: 415-903-2585 |
+---------------------------------------+-----------------------------------+