From: "Martin v. Loewis" <martin@loewis.home.cs.tu-berlin.de>
To: rocombs@cs.nmsu.edu
Cc: gcc@gcc.gnu.org
Subject: Re: Compiler Directive to List Defined Macros?
Date: Thu, 29 Jun 2000 00:39:00 -0000 [thread overview]
Message-ID: <200006290738.JAA00908@loewis.home.cs.tu-berlin.de> (raw)
In-Reply-To: <200006290019.SAA23796@quito.cs.nmsu.edu>
> A few things seem to be missing though. It doesn't show __FILE__, __LINE__,
> __func__, or __PRETTY_FUNCTION__. I understand these are a little different
> since they are "dynamic", but it would be helpful to know which ones are
> avaliable.
The complete list can be found be combining those required by the
standard with those documented in the GCC documentation, in particular
in the section "Function Names".
> The reason I wanted to know was that I had some code like this:
> #ifdef __func__
> /* code using __func__ */
> #else
As Geoff explains, __func__ is not a preprocessor macro. Instead, it
is an identifier. The proper way of testing for it is to write
#if __STDC_VERSION__+0 >= 199901L
since __func__ is defined by C99.
> # ifdef __PRETTY_FUNCTION__
> /* code using __PRETTY_FUNCTION__ */
> # else
> /* code that doewsn't use function names */
> # endif
> #endif
The proper way of testing for these is to write
#ifdef __GNUC__
in which case you can use either one.
> 1) This version of gcc (egcs-2.91.66 from Red Hat 6.1) doesn't support
> __func__, but another version I used did.
Yes, I believe it was added in 2.95.
> 2) This version of gcc doesn't allow detection of __PRETTY_FUNCTION__ with
> #ifdef or #defined.
No, that is not possible - the preprocessor has no way of knowing what
the current function is. That's why they are identifiers, or string
literals.
> But is #2 "fixed" yet?
It's not broken. It can't possibly work the way you expect it to
work. Instead, you must use other tests in portable code.
Regards,
Martin
next prev parent reply other threads:[~2000-06-29 0:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-06-28 17:19 Ross Combs
2000-06-28 19:40 ` Geoff Keating
2000-06-29 0:39 ` Martin v. Loewis [this message]
-- strict thread matches above, loose matches on Subject: below --
2000-06-30 14:34 Ross Combs
2000-06-29 15:49 Ross Combs
2000-06-30 1:36 ` Neil Booth
2000-06-29 8:28 Ross Combs
2000-06-29 13:44 ` Martin v. Loewis
2000-06-29 8:18 Ross Combs
2000-06-29 11:38 ` Geoff Keating
2000-06-28 6:44 Bolan Meek
2000-06-28 7:27 ` Franz Sirl
2000-06-28 7:35 ` Bolan Meek
2000-06-28 7:56 ` Alexandre Oliva
2000-06-28 8:06 ` Bolan Meek
2000-06-28 8:14 ` Alexandre Oliva
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