Paul Eggert wrote:
> > Thus, it's best to avoid such a situation. This holds not only for
> > <stdalign.h> but also for <stdbool.h>. For <assert.h> on the other hand
> > I think the trouble is limited, because <assert.h> always exists among the
> > system header files.
>
> These days stdbool.h falls into pretty much the same category as
> assert.h. As far as I know, every platform currently supported by Gnulib
> that doesn't have a working bool builtin (and thus will include
> stdbool.h) has a stdbool.h that should work well enough for all but the
> most contrarian of uses. So I suggest leaving stdbool.h alone. That way,
> we'll have better luck with Autoconf and AC_C_BOOL.
Indeed, the platforms lacking <stdbool.h> are:
- HP-UX 11, IRIX 6.5 — both not among our target platforms any more,
- Solaris 10 with cc — but here support can be added just by tweaking
$CC. See
<https://gitlab.com/ghwiki/gnow-how/-/wikis/Platforms/Configuration>
So, I'm reverting most of yesterday's change and putting in a #error
instead, to tell the user.
On Solaris 10, this error looks like this:
"../config.h", line 536: #error: "<stdbool.h> is not usable with this
configuration. To make it usable, add -D_STDC_C99= to $CC."
On HP-UX and IRIX, it would look like this:
../config.h: error: "<stdbool.h> does not exist on this platform. Use gnulib
module 'stdbool-c99' instead of gnulib module 'stdbool'."
> stdalign.h is more of a problem as it was introduced in C11 and Gnulib
> doesn't require C11 yet, so we will need a fix along the lines of what
> you suggested, though I wish the code duplication could be avoided.
The code duplication could be avoided by letting gnulib-tool include
lib/stdalign.in.h into the shipped copy of m4/stdalign.m4. I'm still
thinking about how to achieve this in a way that is not a special-case
hack but more useful in general.
2022-09-25 Bruno Haible <br...@clisp.org>
stdbool: Mostly revert last patch.
* m4/c-bool.m4 (gl_C_BOOL): If stdbool.h does not exist, just err out.
* modules/stdbool (Files): Remove m4/stdbool.m4.
diff --git a/ChangeLog b/ChangeLog
index 1c54eabb49..24553445f6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,9 +1,16 @@
+2022-09-25 Bruno Haible <br...@clisp.org>
+
+ stdbool: Mostly revert last patch.
+ * m4/c-bool.m4 (gl_C_BOOL): If stdbool.h does not exist, just err out.
+ * modules/stdbool (Files): Remove m4/stdbool.m4.
+
2022-09-24 Bruno Haible <br...@clisp.org>
stdbool: Don't #include a gnulib-generated stdbool.h from config.h.
* m4/c-bool.m4 (gl_C_BOOL): Check for stdbool.h and for _Bool. If
stdbool.h does not exist, don't #include <stdbool.h> but instead put the
substitute code into config.h.
+ * modules/stdbool (Files): Add m4/stdbool.m4.
2022-09-24 Bruno Haible <br...@clisp.org>
diff --git a/m4/c-bool.m4 b/m4/c-bool.m4
index 129981d2f7..bb109b7796 100644
--- a/m4/c-bool.m4
+++ b/m4/c-bool.m4
@@ -23,8 +23,6 @@ AC_DEFUN([gl_C_BOOL],
fi
AC_CHECK_HEADERS_ONCE([stdbool.h])
- AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
- AC_DEFINE_UNQUOTED([HAVE__BOOL],[$HAVE__BOOL])
dnl The "zz" puts this toward config.h's end, to avoid potential
dnl collisions with other definitions.
@@ -39,39 +37,11 @@ AC_DEFUN([gl_C_BOOL],
# if HAVE_STDBOOL_H
# include <stdbool.h>
# else
- /* Substitute. Keep consistent with gnulib/lib/stdbool.in.h. */
-# ifndef _GL_STDBOOL_H
-# define _GL_STDBOOL_H
-# ifdef __cplusplus
-# if !defined _MSC_VER
-# define _Bool bool
-# define bool bool
-# endif
-# else
-# if !defined __GNUC__
-# define _Bool signed char
-# else
-# if !HAVE__BOOL
-typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool;
-# endif
-# endif
-# define bool _Bool
-# endif
-# ifdef __cplusplus
-# if !defined _MSC_VER
-# define false false
-# define true true
-# endif
-# if defined __SUNPRO_CC && true != 1
-# undef true
-# define true (!false)
-# endif
-# else
-# define false 0
-# define true 1
-# endif
-# define __bool_true_false_are_defined 1
-# endif /* _GL_STDBOOL_H */
+# if defined __SUNPRO_C
+# error "<stdbool.h> is not usable with this configuration. To make it
usable, add -D_STDC_C99= to $CC."
+# else
+# error "<stdbool.h> does not exist on this platform. Use gnulib module
'stdbool-c99' instead of gnulib module 'stdbool'."
+# endif
# endif
# endif
# if !true
diff --git a/modules/stdbool b/modules/stdbool
index 664df5e0f8..2e771a2336 100644
--- a/modules/stdbool
+++ b/modules/stdbool
@@ -3,7 +3,6 @@ A bool that is like C23.
Files:
m4/c-bool.m4
-m4/stdbool.m4
Depends-on:
c99
