From:	Sengan DOT Short AT durham DOT ac DOT uk
Message-Id:	<6020.9607241449@ws-ai5.dur.ac.uk>
Subject:	Re: Multithread question
To:	eliz AT is DOT elta DOT co DOT il (Eli Zaretskii)
Date:	Wed, 24 Jul 1996 15:49:50 +0100 (BST)
Cc:	djgpp AT delorie DOT com
In-Reply-To:	<Pine.SUN.3.91.960724150419.13991B-100000@is> from "Eli Zaretskii" at Jul 24, 96 03:22:16 pm
Mime-Version:	1.0

> Doesn't the LWP package work by converting the interrupt into a signal?  
> If so, then DOS reentrancy isn't an issue, because the signal handling is 
> delayed until you are back in protected mode.

Yes it does, so it's ok.

> >  b) printf is less reentrant than DOS.
> 
> Any function that passes data to or from DOS is non-reentrant because it 
> uses the transfer buffer.  Each task (thread) should allocate its own 
> transfer buffer to be able to freely use real-mode services which need a 
> transfer buffer.  The scheduler (the signal handler) should change the 
> value of _go32_info_block.linear_address_of_transfer_buffer on every task 
> switch, for this to work.

Is that all we have to do? Allocate dos memory, and switch the above value ?

What about malloc: it has a nextf[] structure it uses, so probably is not 
reentrant, right? Do you know of any other functions that might be non-reentrant
like this?

Sengan

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