From owner-freebsd-current  Mon Sep  9  3:45: 7 2002
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Date: Mon, 9 Sep 2002 20:52:38 +1000 (EST)
From: Bruce Evans <bde@zeta.org.au>
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To: Christopher Vance <vance@aurema.com>
Cc: "David O'Brien" <obrien@FreeBSD.ORG>,
	Garrett Wollman <wollman@lcs.mit.edu>, <current@FreeBSD.ORG>,
	<kan@FreeBSD.ORG>
Subject: Re: No way to tell when `long long' is or is not supported?
In-Reply-To: <20020909194232.A25660@aurema.com>
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On Mon, 9 Sep 2002, Christopher Vance wrote:

> On Mon, Sep 09, 2002 at 01:10:46AM -0700, David O'Brien wrote:
> : > Rather than trying to deduce whether `long long' is supported from
> : > other macros, I simply modified the compiler driver to tell us.
>
> What's wrong with
>
> #include <limits.h>
> #ifdef LLONG_MAX
>
> Surely we get to determine the contents of our own limits.h files?

1) Namespace pollution.  Standard headers other than <limits.h> are not
   permitted to define LLONG_MAX.
2) A non-broken <limits.h> would need much the same ifdefs as
   <sys/cdefs.h> for determining whether the compiler and/or standard
   supports long long.  <limits.h> is not permitted to define LLONG_MA
   if the standard is C90 but currently defines it unconditionally.
   The syntax error in the definition of LLONG_MAX doesn't cause many
   problems for C90 compilers because the macro is not normally used
   in C90 environment.  A test like:

#include <limits.h>
#if LLONG_MAX > 0

   would have syntax errors.

Bruce


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