Assume that <stdbool.h> conforms to the C standard.

Previously we checked "for <stdbool.h> that conforms to C99" using
autoconf's AC_HEADER_STDBOOL macro.  We've required C99 since PostgreSQL
12, so the test was redundant, and under C23 it was broken: autoconf
2.69's implementation doesn't understand C23's new empty header (the
macros it's looking for went away, replaced by language keywords).
Later autoconf versions fixed that, but let's just remove the
anachronistic test.

HAVE_STDBOOL_H and HAVE__BOOL will no longer be defined, but they
weren't directly tested in core or likely extensions (except in 11, see
below).  PG_USE_STDBOOL (or USE_STDBOOL in 11 and 12) is still defined
when sizeof(bool) is 1, which should be true on all modern systems.
Otherwise we define our own bool type and values of size 1, which would
fail to compile under C23 as revealed by the broken test.  (We'll
probably clean that dead code up in master, but here we want a minimal
back-patchable change.)

This came to our attention when GCC 15 recently started using using C23
by default and failed to compile the replacement code, as reported by
Sam James and build farm animal alligator.

Back-patch to all supported releases, and then two older versions that
also know about <stdbool.h>, per the recently-out-of-support policy[1].
12 requires C99 so it's much like the supported releases, but 11 only
assumes C89 so it now uses AC_CHECK_HEADERS instead of the overly picky
AC_HEADER_STDBOOL.  (I could find no discussion of which historical
systems had <stdbool.h> but failed the conformance test; if they ever
existed, they surely aren't relevant to that policy's goals.)

[1] https://wiki.postgresql.org/wiki/Committing_checklist#Policies

Reported-by: Sam James <sam@gentoo.org>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org> (master version)
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (approach)
Discussion: https://www.postgresql.org/message-id/flat/87o72eo9iu.fsf%40gentoo.org

diff --git a/configure b/configure
index 90d57f988072794d4f1f3020b6509dd54abe9484..6404ac104476dec07f288bf3df9dd9d96369b77d 100755 (executable)
--- a/configure
+++ b/configure
@@ -2072,116 +2072,116 @@ $as_echo "$ac_res" >&6; }
 
 } # ac_fn_c_check_func
 
-# ac_fn_c_check_type LINENO TYPE VAR INCLUDES
-# -------------------------------------------
-# Tests whether TYPE exists after having included INCLUDES, setting cache
-# variable VAR accordingly.
-ac_fn_c_check_type ()
+# ac_fn_c_check_member LINENO AGGR MEMBER VAR INCLUDES
+# ----------------------------------------------------
+# Tries to find if the field MEMBER exists in type AGGR, after including
+# INCLUDES, setting cache variable VAR accordingly.
+ac_fn_c_check_member ()
 {
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
-$as_echo_n "checking for $2... " >&6; }
-if eval \${$3+:} false; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2.$3" >&5
+$as_echo_n "checking for $2.$3... " >&6; }
+if eval \${$4+:} false; then :
   $as_echo_n "(cached) " >&6
 else
-  eval "$3=no"
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-$4
+$5
 int
 main ()
 {
-if (sizeof ($2))
-    return 0;
+static $2 ac_aggr;
+if (ac_aggr.$3)
+return 0;
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
+  eval "$4=yes"
+else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-$4
+$5
 int
 main ()
 {
-if (sizeof (($2)))
-       return 0;
+static $2 ac_aggr;
+if (sizeof ac_aggr.$3)
+return 0;
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-
+  eval "$4=yes"
 else
-  eval "$3=yes"
+  eval "$4=no"
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 fi
-eval ac_res=\$$3
+eval ac_res=\$$4
           { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
 $as_echo "$ac_res" >&6; }
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
-} # ac_fn_c_check_type
+} # ac_fn_c_check_member
 
-# ac_fn_c_check_member LINENO AGGR MEMBER VAR INCLUDES
-# ----------------------------------------------------
-# Tries to find if the field MEMBER exists in type AGGR, after including
-# INCLUDES, setting cache variable VAR accordingly.
-ac_fn_c_check_member ()
+# ac_fn_c_check_type LINENO TYPE VAR INCLUDES
+# -------------------------------------------
+# Tests whether TYPE exists after having included INCLUDES, setting cache
+# variable VAR accordingly.
+ac_fn_c_check_type ()
 {
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2.$3" >&5
-$as_echo_n "checking for $2.$3... " >&6; }
-if eval \${$4+:} false; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
+$as_echo_n "checking for $2... " >&6; }
+if eval \${$3+:} false; then :
   $as_echo_n "(cached) " >&6
 else
+  eval "$3=no"
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-$5
+$4
 int
 main ()
 {
-static $2 ac_aggr;
-if (ac_aggr.$3)
-return 0;
+if (sizeof ($2))
+    return 0;
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  eval "$4=yes"
-else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-$5
+$4
 int
 main ()
 {
-static $2 ac_aggr;
-if (sizeof ac_aggr.$3)
-return 0;
+if (sizeof (($2)))
+       return 0;
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  eval "$4=yes"
+
 else
-  eval "$4=no"
+  eval "$3=yes"
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 fi
-eval ac_res=\$$4
+eval ac_res=\$$3
           { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
 $as_echo "$ac_res" >&6; }
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
-} # ac_fn_c_check_member
+} # ac_fn_c_check_type
 
 # ac_fn_c_compute_int LINENO EXPR VAR INCLUDES
 # --------------------------------------------
@@ -12910,101 +12910,7 @@ fi
 ## Header files
 ##
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for stdbool.h that conforms to C99" >&5
-$as_echo_n "checking for stdbool.h that conforms to C99... " >&6; }
-if ${ac_cv_header_stdbool_h+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-             #include <stdbool.h>
-             #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
-
-             struct s { _Bool s: 1; _Bool t; } 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];
-             /* 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;
-
-int
-main ()
-{
-
-             bool e = &s;
-             *pq |= q;
-             *pq |= ! 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);
-
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-  ac_cv_header_stdbool_h=yes
-else
-  ac_cv_header_stdbool_h=no
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_header_stdbool_h" >&5
-$as_echo "$ac_cv_header_stdbool_h" >&6; }
-   ac_fn_c_check_type "$LINENO" "_Bool" "ac_cv_type__Bool" "$ac_includes_default"
-if test "x$ac_cv_type__Bool" = xyes; then :
-
-cat >>confdefs.h <<_ACEOF
-#define HAVE__BOOL 1
-_ACEOF
-
-
-fi
-
-
-if test $ac_cv_header_stdbool_h = yes; then
-
-$as_echo "#define HAVE_STDBOOL_H 1" >>confdefs.h
-
-fi
-
-
-for ac_header in atomic.h crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h mbarrier.h poll.h sys/epoll.h sys/ipc.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h
+for ac_header in atomic.h crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h mbarrier.h poll.h stdbool.h sys/epoll.h sys/ipc.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"

diff --git a/configure.in b/configure.in
index b092510077405d747b5cda5e0a009b791d6f8dab..82f4c618aaabc504b7d02fb2d5040cd2185c4ff0 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1392,9 +1392,7 @@ AC_SUBST(UUID_LIBS)
 ## Header files
 ##
 
-AC_HEADER_STDBOOL
-
-AC_CHECK_HEADERS([atomic.h crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h mbarrier.h poll.h sys/epoll.h sys/ipc.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h])
+AC_CHECK_HEADERS([atomic.h crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h mbarrier.h poll.h stdbool.h sys/epoll.h sys/ipc.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h])
 
 # On BSD, test for net/if.h will fail unless sys/socket.h
 # is included first.

diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 157b504ea6a7568ed1d0747e367e206d2d3fc94c..7407145f5e2e4b18685a4650efaffab6920a22d9 100644 (file)
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -507,7 +507,7 @@
 /* Define to 1 if you have the `SSL_get_current_compression' function. */
 #undef HAVE_SSL_GET_CURRENT_COMPRESSION
 
-/* Define to 1 if stdbool.h conforms to C99. */
+/* Define to 1 if you have the <stdbool.h> header file. */
 #undef HAVE_STDBOOL_H
 
 /* Define to 1 if you have the <stdint.h> header file. */
@@ -721,9 +721,6 @@
 /* Define to 1 if you have the `X509_get_signature_nid' function. */
 #undef HAVE_X509_GET_SIGNATURE_NID
 
-/* Define to 1 if the system has the type `_Bool'. */
-#undef HAVE__BOOL
-
 /* Define to 1 if your compiler understands __builtin_bswap16. */
 #undef HAVE__BUILTIN_BSWAP16
 

diff --git a/src/include/pg_config.h.win32 b/src/include/pg_config.h.win32
index d2149996d2938b3f53057d36b8caa532bcd513fe..88ff1a6db79c8b5ebde3ad2998812e95d1ae572d 100644 (file)
--- a/src/include/pg_config.h.win32
+++ b/src/include/pg_config.h.win32
@@ -574,9 +574,6 @@
 /* Define to 1 if you have the `X509_get_signature_nid' function. */
 #define HAVE_X509_GET_SIGNATURE_NID 1
 
-/* Define to 1 if the system has the type `_Bool'. */
-/* #undef HAVE__BOOL */
-
 /* Define to 1 if your compiler understands __builtin_bswap16. */
 /* #undef HAVE__BUILTIN_BSWAP16 */