[M3devel] nt386gnu threads?

[Tony Hosking]

On Jan 28, 2008, at 6:29 AM, Jay wrote:

> Can anyone confirm my read that PM3's NT386GNU used user/vtalarm  
> threads?

Indeed.  Pthread support has only been available in CM3 since I  
started on it in in 2006.  Thus, unless it was using Win32 threads it  
had to have been SIGVTALRM based (ie, implemented as in ThreadPosix.m3).

> PM3 appears to have no PThread support ant its NT386GNU appears to  
> have OS_TYPE=POSIX.
> Heck, even its NT386 has OS_TYPE=POSIX, but its NT386 is probably  
> dead/broken.
>
> 1) I'm too lazy to tediously rewrite Cygwin's pthread.h et. al.  
> into Modula-3.

I am unfamiliar with Cygwin pthread support.  Are they layered on  
win32 threads?  It is not terribly hard to write Upthread.i3 and  
friends.

> 2) The thread library you pick is not an independent decision.
>  The Modula-3 File I/O libraries interact with the threading  
> library at least a little bit.

The POSIX file IO libraries are known to function with both  
ThreadPThread and ThreadPosix (SIGVTALRM).  Thus, you should be able  
to use them cleanly if the Cygwin-based Modula-3 implementation takes  
on a purely/mainly POSIX personality (as many of us have argued it  
should!).

> The path of less resistance seems to be user/vtalarm threads for  
> now, until
> such time as Cygwin Upthread.i3 is written.

Yes, indeed.

> (That is, neither pthreads nor win32 satisfied my laziness; I'm  
> going to try user/vtalarm threads, see how it goes; I'm sure they  
> aren't very good, but...)

Certainly, you won't get any multicore benefit with SIGVTALRM-based  
threads.