Paul Eggert wrote: > I installed the attached patch into Gnulib, reflecting a patch I > recently installed into Autoconf > <https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=6dcecb780a69bd208088d666b299e92aa7ae7e80>. > > I think we need a new Autoconf macro that obsoletes AC_HEADER_STDBOOL > and AC_CHECK_HEADER_STDBOOL. This new macro should arrange for 'bool', > 'true' and 'false' to work, without programs having to include > stdbool.h. For C23 and C++ the new macro should do nothing. For C99 > through C17 it should include <stdbool.h> in config.h. For pre-C99 it > should #define bool, true, and false in config.h. The requirement "For C99 through C17 it should include <stdbool.h> in config.h" is a problem. In our experience, including OS headers from config.h leads to issues, namely: - other definitions in config.h may not work if OS headers have already been included, - some packages have multiple config.h, and the second one may not work once the first one has included OS headers, - the programmer may have assumed that '#include <config.h>' did not include anything from the OS. The first of these problems may be resolved by ensuring that the '#include <stdbool.h>' goes to the end of config.h, not to a random place in the middle. But to exclude other problems, we need to check it on a platform-by-platform basis. As a first step towards this goal, let's "handle" BeOS by dropping the BeOS support. 2022-08-15 Bruno Haible <bruno@xxxxxxxxx> stdbool: Drop old BeOS support that gets in the way of ISO C 23 support. * lib/stdbool.in.h: Don't include <OS.h>. diff --git a/lib/stdbool.in.h b/lib/stdbool.in.h index 03840f10fc..2fa46724b2 100644 --- a/lib/stdbool.in.h +++ b/lib/stdbool.in.h @@ -58,27 +58,11 @@ /* 7.16. Boolean type and values */ -/* BeOS <sys/socket.h> already #defines false 0, true 1. We use the same - definitions below, but temporarily we have to #undef them. */ -#if defined __BEOS__ && !defined __HAIKU__ -# include <OS.h> /* defines bool but not _Bool */ -# undef false -# undef true -#endif - #ifdef __cplusplus # define _Bool bool # define bool bool #else -# if defined __BEOS__ && !defined __HAIKU__ - /* A compiler known to have 'bool'. */ - /* If the compiler already has both 'bool' and '_Bool', we can assume they - are the same types. */ -# if !@HAVE__BOOL@ -typedef bool _Bool; -# endif -# else -# if !defined __GNUC__ +# if !defined __GNUC__ /* If @HAVE__BOOL@: Some HP-UX cc and AIX IBM C compiler versions have compiler bugs when the built-in _Bool type is used. See @@ -98,10 +82,10 @@ typedef bool _Bool; "Invalid enumerator. (badenum)" with HP-UX cc on Tru64. The only benefit of the enum, debuggability, is not important with these compilers. So use 'signed char' and no enum. */ -# define _Bool signed char -# else +# define _Bool signed char +# else /* With this compiler, trust the _Bool type if the compiler has it. */ -# if !@HAVE__BOOL@ +# if !@HAVE__BOOL@ /* For the sake of symbolic names in gdb, define true and false as enum constants, not only as macros. It is tempting to write @@ -112,7 +96,6 @@ typedef bool _Bool; (see ISO C 99 6.3.1.1.(2)). So add a negative value to the enum; this ensures that '_Bool' promotes to 'int'. */ typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool; -# endif # endif # endif # define bool _Bool
