On 02/28/2012 07:46 PM, Bruno Haible wrote: > Eric Blake wrote: >> I'm leaning towards "#define noreturn /**/" as well. > > Me too. It's the most reliable, will not give us surprises.
Thanks, I pushed this: >From 44cc63109021dd9aa88d1736536581cf08fce29a Mon Sep 17 00:00:00 2001 From: Paul Eggert <egg...@cs.ucla.edu> Date: Wed, 29 Feb 2012 01:48:18 -0800 Subject: [PATCH] stdnoreturn: port to MSVC better MSVC standard headers use __declspec(noreturn), so #define noreturn to empty on that platform. Reported by Bruno Haible in <http://lists.gnu.org/archive/html/bug-gnulib/2012-02/msg00152.html>. * lib/stdnoreturn.in.h (noreturn): Define to empty on MSVC. * doc/posix-headers/stdnoreturn.texi (stdnoreturn.h): Document this. --- ChangeLog | 9 +++++++++ doc/posix-headers/stdnoreturn.texi | 8 ++++++++ lib/stdnoreturn.in.h | 14 +++++++++++++- 3 files changed, 30 insertions(+), 1 deletions(-) diff --git a/ChangeLog b/ChangeLog index 2294d7c..37ad125 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2012-02-29 Paul Eggert <egg...@cs.ucla.edu> + + stdnoreturn: port to MSVC better + MSVC standard headers use __declspec(noreturn), so #define noreturn + to empty on that platform. Reported by Bruno Haible in + <http://lists.gnu.org/archive/html/bug-gnulib/2012-02/msg00152.html>. + * lib/stdnoreturn.in.h (noreturn): Define to empty on MSVC. + * doc/posix-headers/stdnoreturn.texi (stdnoreturn.h): Document this. + 2012-02-28 Bruno Haible <br...@clisp.org> doc: Mention new glibc headers and functions. diff --git a/doc/posix-headers/stdnoreturn.texi b/doc/posix-headers/stdnoreturn.texi index f49d663..a7dab0f 100644 --- a/doc/posix-headers/stdnoreturn.texi +++ b/doc/posix-headers/stdnoreturn.texi @@ -21,4 +21,12 @@ Portability problems not fixed by Gnulib: @item You cannot assume that @code{_Noreturn} is a reserved word; it might be a macro. +@item +On MSVC 9, @code{noreturn} expands to the empty token sequence, to avoid +problems with standard headers that use @code{__declspec (noreturn)} +directly. Although the resulting code operates correctly, the +compiler is not informed whether @code{noreturn} functions do not +return, so it may generate incorrect warnings at compile-time, or code +that is slightly less optimized. This problem does not occur with +@code{_Noreturn}. @end itemize diff --git a/lib/stdnoreturn.in.h b/lib/stdnoreturn.in.h index 5ca3063..ab9202e 100644 --- a/lib/stdnoreturn.in.h +++ b/lib/stdnoreturn.in.h @@ -28,7 +28,19 @@ /* The definition of _Noreturn is copied here. */ -#define noreturn _Noreturn +#if 1200 <= _MSC_VER +/* Standard include files on this platform contain declarations like + "__declspec (noreturn) void abort (void);". "#define noreturn + _Noreturn" would cause this declaration to be rewritten to the + invalid "__declspec (__declspec (noreturn)) void abort (void);". + Instead, define noreturn to empty, so that such declarations are + rewritten to "__declspec () void abort (void);", which is + equivalent to "void abort (void);"; this gives up on noreturn's + advice to the compiler but at least it is valid code. */ +# define noreturn /*empty*/ +#else +# define noreturn _Noreturn +#endif /* Did he ever return? No he never returned -- 1.7.6.5
