Date: Tue, 8 Jun 1999 15:05:44 -0400
Message-Id: <199906081905.PAA23218@envy.delorie.com>
From: DJ Delorie <dj AT delorie DOT com>
To: rudd AT cyberoptics DOT com
CC: eliz AT is DOT elta DOT co DOT il, djgpp-workers AT delorie DOT com
In-reply-to: <375D4DF1.5F3B39F9@cyberoptics.com> (message from Eric Rudd on
	Tue, 08 Jun 1999 12:08:01 -0500)
Subject: Re: libm sources from cyberoptics
References: <Pine DOT SUN DOT 3 DOT 91 DOT 990608112417 DOT 4197A-100000 AT is> <375D4DF1 DOT 5F3B39F9 AT cyberoptics DOT com>
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[For those of you just joining us: we're talking about new math
routines found at ftp://ftp.delorie.com/private/from_erudd.zip - DJ]

> There are a number of routines that are non-reentrant.  If it is
> important for them to be reentrant, I will have to fix them.

The issue of libc reentrancy came up recently.  It doesn't make sense
to create new non-reentrant functions if we know people are concerned
with reentrancy.

> >   8) I understand that we need to keep the old version of modfl, since
> >      there's no new one, right?
> 
> This is a long double (non-ANSI) routine.  I don't know why the old
> libc had it, since practically no other long double routines were
> furnished.  For compatibility, we should retain it, however.

printf needs it for long double support, I think.

> I had a discussion with DJ about the necessity for stubs; I have to
> go back and look that over again, since I didn't entirely understand
> the need for them.

Stubs are needed when a function defined by one spec calls a function
that isn't defined by that spec.  For example, if printf() calls
modfl(), and printf() is ANSI but modfl() violates ANSI, then we
replace modfl() with __modfl() (which is OK with ANSI) and create a
stub called modfl() that simply calls __modfl().  That way, using
printf() won't pollute your ANSI namespace with other functions,
because now it's only calling __modfl().