Tony Finch wrote:
> > > No -- the short-circuiting behaviour of && and || only matters if
> > > you can have side-effects, which you can't in the preprocessor,
> > > so there is no need to implement it (unifdef doesn't).
> >
> > Consider:
> >
> > #if _DEFINED_SUPPORTED && defined(SOMETHING)
>
>
On Sat, Oct 12, 2002 at 01:20:03PM -0700, Terry Lambert wrote:
> Tony Finch wrote:
> >
> > No -- the short-circuiting behaviour of && and || only matters if
> > you can have side-effects, which you can't in the preprocessor,
> > so there is no need to implement it (unifdef doesn't).
>
> Consider
Tony Finch wrote:
> > With just an "&" or an "|", you actually need a much less complicated
> > state machine to evaluate a constant expression. With the "||"/"&&",
> > you almost have to do an edge associative operation, which implies a
> > much more complex state machine for the preprocessor, I
On Sat, Oct 12, 2002 at 01:44:36AM -0700, Terry Lambert wrote:
>
> I think the lack of "||" and "&&" mostly had to do with the fact
> that there was conditional evaluation of the RHS of the operator,
> based on the result of the LHS.
>
> With just an "&" or an "|", you actually need a much less
Bruce Evans wrote:
> This book has lots of bugs (mostly from being too informal and/or
> omitting necessary details). Note that section 15 doesn't even mention
> "&&" and "||" working in non-cpp constant expressions. But they
> cetainly worked in expressions, and expressions with only constants
>
On Fri, 11 Oct 2002, Terry Lambert wrote:
> Bruce Evans wrote:
> > > I know it's not fashionable to write code that's portable to
> > > compilers other than GCC, but even if FreeBSD is going to ignore
> > > portability for it's own source code, it's probably unreasonable
> > > to expect ACE to ign
Bruce Evans wrote:
> _POSIX_REALTIME_SIGNALS is only valid in versions of POSIX that support
> it. Applications must also conditionalize on _POSIX_VERSION if they
> want to check for features that are not in all versions.
Yeah; I mentioned that I was afraid of this...
> Runtime configuration o
Bruce Evans wrote:
> > I know it's not fashionable to write code that's portable to
> > compilers other than GCC, but even if FreeBSD is going to ignore
> > portability for it's own source code, it's probably unreasonable
> > to expect ACE to ignore portability for theirs.
>
> Undefined symbols b
On Thu, 10 Oct 2002, Craig Rodrigues wrote:
> On Thu, Oct 10, 2002 at 09:31:56PM +1000, Bruce Evans wrote:
> > Perhaps because they wanted you to use sysconf() instead of these mistakes.
>
> Well in the case of ACE, it is a C++ library that is compiled on
> platforms which may or may not have sysc
On Thu, 10 Oct 2002, Terry Lambert wrote:
> Bruce Evans wrote:
> > _POSIX_REALTIME_SIGNALS is undefined:
> > Apparently the same as when it is defined to 0, except you cannot assume
> > that anything related to it works until you call sysconf(), so you must
> > not reference its interfaces static
On Thu, 10 Oct 2002, Terry Lambert wrote:
> Bruce Evans wrote:
> > In Standard C, this is equivalent to the non-verbose version:
> >
> > #if _POSIX_REALTIME_SIGNALS != -1
> > ...
> > #endif
> >
> > since if _POSIX_REALTIME_SIGNALS is not defined then it is equivalent to
>
Bruce Evans wrote:
> _POSIX_REALTIME_SIGNALS is defined to 0:
> This means that the interface may work, and that it exists in headers and
> libraries, so applications may reference it in normal ways. It may fail
> at runtime; applications must use sysconf() to determine if it is actually
Alterna
Bruce Evans wrote:
> In Standard C, this is equivalent to the non-verbose version:
>
> #if _POSIX_REALTIME_SIGNALS != -1
> ...
> #endif
>
> since if _POSIX_REALTIME_SIGNALS is not defined then it is equivalent to
> 0 in cpp expressions. The problem cases are if _POSIX_RE
Giorgos Keramidas wrote:
> > I think the first is safer, in that if "#if" is not supported, it
> > being an undefined preprocessor directive would be non-fatal,
> > being in an uncompiled "#ifdef" block...
>
> Well, almost. There is one exception. A compiler that doesn't support
> #if but happe
On Thu, Oct 10, 2002 at 09:31:56PM +1000, Bruce Evans wrote:
> Perhaps because they wanted you to use sysconf() instead of these mistakes.
Well in the case of ACE, it is a C++ library that is compiled on
platforms which may or may not have sysconf() (ie. Windows), so using sysconf() is
not practi
On 2002-10-10 01:07, Terry Lambert <[EMAIL PROTECTED]> wrote:
>
> So the test is:
>
> #ifdef _POSIX_REALTIME_SIGNALS
> #if _POSIX_REALTIME_SIGNALS > 0
>
> ...or, if you want to assume all preprocessors support "#if":
>
> #if defined(_POSIX_REALTIME_SIGNALS) && (_POSIX_REALTIME_SIGNALS > 0)
>
> I t
On Wed, 9 Oct 2002, Craig Rodrigues wrote:
> Earlier this year on the FreeBSD hackers mailing list:
>
>http://docs.freebsd.org/cgi/getmsg.cgi?fetch=278142+0+/usr/local/www/db/text/2002/freebsd-hackers/20020317.freebsd-hackers
>
> I was advised by Terry Lambert to use:
> #ifdef _POSIX_REALTIME_SI
On Wed, 9 Oct 2002, Craig Rodrigues wrote:
> On Wed, Oct 09, 2002 at 07:29:48PM -0700, Terry Lambert wrote:
> > To be totally correct, you will need to:
> >
> > #ifdef _POSIX_REALTIME_SIGNALS
> > #if (_POSIX_REALTIME_SIGNALS != -1)
> >
> > ...
> >
> > #endif
> > #endif
> >
> >
Garrett Wollman wrote:
> < said:
> > I was advised by Terry Lambert to use:
> > #ifdef _POSIX_REALTIME_SIGNALS
>
> Terry was wrong. If _POSIX_REALTIME_SIGNALS is undefined, it means
> one of two things:
>
> - The RTS option is not supported, or
That's what I said in the orignal posting. He ne
On Wed, Oct 09, 2002 at 07:29:48PM -0700, Terry Lambert wrote:
> To be totally correct, you will need to:
>
> #ifdef _POSIX_REALTIME_SIGNALS
> #if (_POSIX_REALTIME_SIGNALS != -1)
>
> ...
>
> #endif
> #endif
>
> It's annoying, but doing this will ensure that there
Craig Rodrigues wrote:
> #ifdef _POSIX_REALTIME_SIGNALS
> According to the letter of the law:
> http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap02.html
>
> "The following symbolic constants shall either be undefined or defined
> with a value other than -1."
>
> So, this is legal
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