🚀 go-pugleaf

In article <2573@cronos.metaphor.com> eli@Metaphor.COM (Eli Lauris) writes:
> Hi,
> 
> I am working on porting a complex OS/2 application to Windows 3.1 (Yah, you 
> heard it right: OS2 to Windows, not the other way). The application consists
> of multiple processes and multiple DLL running on top of OS/2 2.0.  
> 
> What I am looking for is a nice development environment for Windows 3.1 that  
> will provide the following:
> 
> 1. 32-bit protected mode environment

There are a number of compilers on the market to do this (Watcom, Zortech,  
etc).  Best read the FAQ (or even flick through a Windows techno-jock  
magazine).

> 2. Multi-threading support

I have seen at least one third-party thread library advertised (in Windows Tech  
Journal, I think).  PCThreads, The TriTechnologies Company, (206)957-1579,  
Compuserve 70272,3671  also had a demo app/library which ran OK under 3.0, but  
does not work with 3.1.  They may have finished the 3.1 product by now; I've  
not had any experience with it.

It's also feasible (and very educational :-) ) to write your own thread  
library. I managed to port the unix c-threads library to Windows, and it has  
stuff like conditional variables, semaphores, etc.  However, if you *really*  
need pre-emptive scheduling (as opposed to sprinkling calls to ThreadYield() in  
your code)......

> 3. Pre-emptive scheduling of processes/threads

I'm not sure this is *possible* under Windows. You really need kernel support  
to do this in a way which is not so ugly as to make you weep.  It may be  
possible to hook the timer interrupt, but the only re-entrant Windows function  
is PostMessage, which does not actually swap the process (let alone the thread)  
in.  At least that's what the docs say.  It may be possible to hook the timer  
and do a DirectedYield().  Has anybody tried this?  The library mentioned above  
claims pre-emption, but I can't vouch for it.

> 4. DLLs that have both instance and shared data

Quite easy, although you need to pass the task id as a parameter to any  
function within the DLL that returns data.

> 5. Inter-process semaphores

Inter-process semaphores can be implemented with shared global memory and a DLL  
to manipulate the data structures. 

> I know its a little bit too much to ask for. After all, when you are done  
providing it, you pretty much have your OS/2 or NT.

Yep.  But don't forget about *real* memory protection, network support,  
security, *real* threads, no 640K crud, no interfering TSR's, long filenames,  
virtual addressing, etc, etc, etc.


Cameron.

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Cameron Bromley                       Internet: cdb@codex.oz.au
Codex Software Development Pty. Ltd.  NextMail encouraged
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