From f960bc91cd325cee7e1262944ca6114bfd4d1c1f Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sat, 13 Aug 2022 20:00:02 -0700 Subject: [PATCH] stdbool: port to C23 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * m4/stdbool.m4 (AC_CHECK_HEADER_STDBOOL): Copy from bleeding-edge Autoconf. Don’t define if Autoconf 2.72 or later. * tests/test-stdbool.c (bool, false, true) (__bool_true_false_are_defined): Do not require these to be defined. C23 still requires __bool_true_false_are_defined but marks it as obsolescent, and it’s no longer worth testing. (WORKING_BOOL): New macro, which also tests __STDC_VERSION__. Use it in tests for working bool. Test for bool instead of for _Bool, which C23 says is obsolescent. --- ChangeLog | 13 ++++++ m4/stdbool.m4 | 105 ++++++++++++++++++++++--------------------- tests/test-stdbool.c | 41 ++++++++--------- 3 files changed, 84 insertions(+), 75 deletions(-) diff --git a/ChangeLog b/ChangeLog index e0bf24fc90..eecf44ba01 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,16 @@ +2022-08-13 Paul Eggert + + stdbool: port to C23 + * m4/stdbool.m4 (AC_CHECK_HEADER_STDBOOL): Copy from bleeding-edge + Autoconf. Don’t define if Autoconf 2.72 or later. + * tests/test-stdbool.c (bool, false, true) + (__bool_true_false_are_defined): Do not require these to be + defined. C23 still requires __bool_true_false_are_defined but + marks it as obsolescent, and it’s no longer worth testing. + (WORKING_BOOL): New macro, which also tests __STDC_VERSION__. + Use it in tests for working bool. + Test for bool instead of for _Bool, which C23 says is obsolescent. + 2022-08-13 Bruno Haible gnulib-tool.py: Fix some code generation details. diff --git a/m4/stdbool.m4 b/m4/stdbool.m4 index 3e6c400546..c67908aa87 100644 --- a/m4/stdbool.m4 +++ b/m4/stdbool.m4 @@ -43,75 +43,76 @@ AC_DEFUN([gl_STDBOOL_H], AC_SUBST([HAVE__BOOL]) ]) -# This version of the macro is needed in autoconf <= 2.68. +m4_version_prereq([2.72], [], [ AC_DEFUN([AC_CHECK_HEADER_STDBOOL], - [AC_CACHE_CHECK([for stdbool.h that conforms to C99], + [AC_CHECK_TYPES([_Bool]) + AC_CACHE_CHECK([for stdbool.h that conforms to C99 or later], [ac_cv_header_stdbool_h], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( - [[ - #include - - #ifdef __cplusplus - typedef bool Bool; - #else - typedef _Bool Bool; - #ifndef bool - "error: bool is not defined" - #endif - #ifndef false - "error: false is not defined" - #endif - #if false - "error: false is not 0" - #endif - #ifndef true - "error: true is not defined" - #endif - #if true != 1 - "error: true is not 1" - #endif + [[#include + + /* "true" and "false" should be usable in #if expressions and + integer constant expressions, and "bool" should be a valid + type name. + + Although C 1999 requires bool, true, and false to be macros, + C 2023 and C++ 2011 overrule that, so do not test for that. + Although C 1999 requires __bool_true_false_are_defined and + _Bool, C 2023 says they are obsolescent, so do not require + them. */ + + #if !true + #error "'true' is not true" + #endif + #if true != 1 + #error "'true' is not equal to 1" #endif + char b[true == 1 ? 1 : -1]; + char c[true]; - #ifndef __bool_true_false_are_defined - "error: __bool_true_false_are_defined is not defined" + #if false + #error "'false' is not false" + #endif + #if false != 0 + #error "'false' is not equal to 0" #endif + char d[false == 0 ? 1 : -1]; + + enum { e = false, f = true, g = false * true, h = true * 256 }; + + char i[(bool) 0.5 == true ? 1 : -1]; + char j[(bool) 0.0 == false ? 1 : -1]; + char k[sizeof (bool) > 0 ? 1 : -1]; + + struct sb { bool s: 1; bool t; } s; + char l[sizeof s.t > 0 ? 1 : -1]; - 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 g[true]; - 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]; - char o[sizeof n == m * sizeof n[0] ? 1 : -1]; - char p[-1 - (Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1]; + bool m[h]; + char n[sizeof m == h * sizeof m[0] ? 1 : -1]; + char o[-1 - (bool) 0 < 0 ? 1 : -1]; /* Catch a bug in an HP-UX C compiler. See https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html */ - Bool q = true; - Bool *pq = &q; - bool *qq = &q; + bool p = true; + bool *pp = &p; ]], [[ - bool e = &s; - *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 + !qq); + bool ps = &s; + *pp |= p; + *pp |= ! p; + + /* Refer to every declared value, so they cannot be + discarded as unused. */ + return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !j + !k + + !l + !m + !n + !o + !p + !pp + !ps); ]])], [ac_cv_header_stdbool_h=yes], [ac_cv_header_stdbool_h=no])]) - AC_CHECK_TYPES([_Bool]) -]) +])# AC_CHECK_HEADER_STDBOOL + +]) # m4_version_prereq 2.72 diff --git a/tests/test-stdbool.c b/tests/test-stdbool.c index 3574a9e72f..27fd16d010 100644 --- a/tests/test-stdbool.c +++ b/tests/test-stdbool.c @@ -35,35 +35,30 @@ #include -#ifndef bool - "error: bool is not defined" -#endif -#ifndef false - "error: false is not defined" -#endif #if false "error: false is not 0" #endif -#ifndef true - "error: true is not defined" -#endif #if true != 1 "error: true is not 1" #endif -#ifndef __bool_true_false_are_defined - "error: __bool_true_false_are_defined is not defined" -#endif /* Several tests cannot be guaranteed with gnulib's , at least, not for all compilers and compiler options. */ -#if HAVE_STDBOOL_H || 3 <= __GNUC__ || 4 <= __clang_major__ -struct s { _Bool s: 1; _Bool t; } s; +#if (202311 <= __STDC_VERSION__ || defined __cplusplus \ + || HAVE_STDBOOL_H || 3 <= __GNUC__ || 4 <= __clang_major__) +# define WORKING_BOOL 1 +#else +# define WORKING_BOOL 0 +#endif + +#if WORKING_BOOL +struct s { bool s: 1; bool t; } s; #endif char a[true == 1 ? 1 : -1]; char b[false == 0 ? 1 : -1]; char c[__bool_true_false_are_defined == 1 ? 1 : -1]; -#if HAVE_STDBOOL_H || 3 <= __GNUC__ || 4 <= __clang_major__ /* See above. */ +#if WORKING_BOOL char d[(bool) 0.5 == true ? 1 : -1]; # ifdef ADDRESS_CHECK_OKAY /* Avoid gcc warning. */ /* C99 may plausibly be interpreted as not requiring support for a cast from @@ -73,30 +68,30 @@ char d[(bool) 0.5 == true ? 1 : -1]; bool e = &s; # endif # endif -char f[(_Bool) 0.0 == false ? 1 : -1]; +char f[(bool) 0.0 == false ? 1 : -1]; #endif char g[true]; -char h[sizeof (_Bool)]; -#if HAVE_STDBOOL_H || 3 <= __GNUC__ || 4 <= __clang_major__ /* See above. */ +char h[sizeof (bool)]; +#if WORKING_BOOL char i[sizeof s.t]; #endif enum { j = false, k = true, l = false * true, m = true * 256 }; -_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 https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html */ -_Bool q = true; -_Bool *pq = &q; +bool q = true; +bool *pq = &q; int main () { int error = 0; -#if HAVE_STDBOOL_H || 3 <= __GNUC_ || 4 <= __clang_major___ /* See above. */ +#if WORKING_BOOL # ifdef ADDRESS_CHECK_OKAY /* Avoid gcc warning. */ /* A cast from a variable's address to bool is valid in expressions. */ { -- 2.34.1