David Seifert wrote:
attached the patch. I believe this patch in fact increases strictness even for C code, as it relies on the proper functioning of the "bool" macro. I have tested it with multiple C and C++ compilers on OS X and Linux:
Thanks, and sorry about the late reply. I installed the attached patch into Gnulib; I think it should solve the problem in a somewhat-different way.
>From f2f0962f49f89ccb2463b3336cae2ad271954047 Mon Sep 17 00:00:00 2001 From: Paul Eggert <egg...@cs.ucla.edu> Date: Wed, 17 Aug 2016 15:33:06 -0700 Subject: [PATCH] stdbool: don't require _Bool for C++ Problem reported by David Seifert in: http://lists.gnu.org/archive/html/bug-gnulib/2016-06/msg00005.html * NEWS, doc/posix-headers/stdbool.texi (stdbool.h): Document this. * m4/stdbool.m4 (AC_CHECK_HEADER_STDBOOL): Make the check more-forgiving for C++, in that it requires only 'bool'. Be a bit stricter about checking that bool and _Bool are compatible in C. --- ChangeLog | 10 ++++++++++ NEWS | 4 ++++ doc/posix-headers/stdbool.texi | 3 ++- m4/stdbool.m4 | 28 ++++++++++++++++------------ 4 files changed, 32 insertions(+), 13 deletions(-) diff --git a/ChangeLog b/ChangeLog index e899eb4..ddacf1e 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,13 @@ +2016-08-17 Paul Eggert <egg...@cs.ucla.edu> + + stdbool: don't require _Bool for C++ + Problem reported by David Seifert in: + http://lists.gnu.org/archive/html/bug-gnulib/2016-06/msg00005.html + * NEWS, doc/posix-headers/stdbool.texi (stdbool.h): Document this. + * m4/stdbool.m4 (AC_CHECK_HEADER_STDBOOL): Make the check + more-forgiving for C++, in that it requires only 'bool'. Be a bit + stricter about checking that bool and _Bool are compatible in C. + 2016-08-16 Paul Eggert <egg...@cs.ucla.edu> getdelim: remove dependency on realloc-posix diff --git a/NEWS b/NEWS index 00709e8..e33d350 100644 --- a/NEWS +++ b/NEWS @@ -42,6 +42,10 @@ User visible incompatible changes Date Modules Changes +2016-08-17 stdbool This no longer supports _Bool for C++. + Programs intended to be portable to C++ + compilers should use plain 'bool' instead. + 2016-04-12 intprops The following macros were removed: TYPE_TWOS_COMPLEMENT TYPE_ONES_COMPLEMENT TYPE_SIGNED_MAGNITUDE diff --git a/doc/posix-headers/stdbool.texi b/doc/posix-headers/stdbool.texi index 50afbd4..bac30aa 100644 --- a/doc/posix-headers/stdbool.texi +++ b/doc/posix-headers/stdbool.texi @@ -20,7 +20,8 @@ OpenBSD 4.7 with gcc 2.95. Portability problems not fixed by Gnulib: @itemize @item -@code{<stdbool.h>} must be #included before @samp{_Bool} can be used. +@samp{_Bool} cannot be used before @code{<stdbool.h>} is included, or if +the program is intended to be compiled by a C++ compiler. @item You cannot assume that @code{_Bool} is a typedef; it might be a macro. @item diff --git a/m4/stdbool.m4 b/m4/stdbool.m4 index a556153..2a9b1db 100644 --- a/m4/stdbool.m4 +++ b/m4/stdbool.m4 @@ -5,7 +5,7 @@ dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. -#serial 6 +#serial 7 # Prepare for substituting <stdbool.h> if it is not supported. @@ -44,7 +44,10 @@ AC_DEFUN([AC_CHECK_HEADER_STDBOOL], [[ #include <stdbool.h> - #if __cplusplus < 201103 + #ifdef __cplusplus + typedef bool Bool; + #else + typedef _Bool Bool; #ifndef bool "error: bool is not defined" #endif @@ -66,37 +69,38 @@ AC_DEFUN([AC_CHECK_HEADER_STDBOOL], "error: __bool_true_false_are_defined is not defined" #endif - struct s { _Bool s: 1; _Bool t; } s; + struct s { Bool s: 1; Bool t; bool u: 1; bool v; } s; char a[true == 1 ? 1 : -1]; char b[false == 0 ? 1 : -1]; char c[__bool_true_false_are_defined == 1 ? 1 : -1]; char d[(bool) 0.5 == true ? 1 : -1]; /* See body of main program for 'e'. */ - char f[(_Bool) 0.0 == false ? 1 : -1]; + char f[(Bool) 0.0 == false ? 1 : -1]; char g[true]; - char h[sizeof (_Bool)]; + char h[sizeof (Bool)]; char i[sizeof s.t]; enum { j = false, k = true, l = false * true, m = true * 256 }; /* The following fails for HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */ - _Bool n[m]; + Bool n[m]; char o[sizeof n == m * sizeof n[0] ? 1 : -1]; - char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1]; + char p[-1 - (Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1]; /* Catch a bug in an HP-UX C compiler. See http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html */ - _Bool q = true; - _Bool *pq = &q; + Bool q = true; + Bool *pq = &q; + bool *qq = &q; ]], [[ bool e = &s; - *pq |= q; - *pq |= ! q; + *pq |= q; *pq |= ! q; + *qq |= q; *qq |= ! q; /* Refer to every declared value, to avoid compiler optimizations. */ return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l - + !m + !n + !o + !p + !q + !pq); + + !m + !n + !o + !p + !q + !pq + !qq); ]])], [ac_cv_header_stdbool_h=yes], [ac_cv_header_stdbool_h=no])]) -- 2.5.5
