Date: Tue, 27 Sep 94 22:40:23 EDT
From: peprbv AT cfa0 DOT harvard DOT edu (Bob Babcock)
To: buers AT dg1 DOT chemie DOT uni-konstanz DOT de
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: int86 vs. _go32_dpmi_simulate_int, bug?
Reply-To: babcock AT cfa DOT harvard DOT edu

> I tried this with other functions as well (MSDOS mkdir, get-version, get-date
> get-time). They all show the same behaviour. With go32_dpmi...  the program
> will not work when the 0x0100 bit of flags is set, and go32 is running in
> non-dpmi mode. int86 will always work.

0x0100 is the single-step bit of the flags register.  I can see how setting
that might be a dangerous thing to do.

> From reading this mailing list, I got the feeling, that calling
> _go32_dpmi_simulate_int is the more modern way to call interrupts.
> Is there some special reason for this? 

The _big_ advantage of doing it this way is that you can use interrupts which
are not supported by the DOS extender.  And it isn't just a question of what
GO32 supports.  Under dpmi, it may well be OS/2, Windows, QDPMI or 386MAX
which is servicing your interrupt calls.  My particular experience is that
FCB functions, which are needed for dealing with disk volume labels, tend to
be poorly supported by DOS extenders.