Thread

[PATCH v5 4/4] Use stdbool.h if available

Peter Eisentraut <peter_e@gmx.net> — 2017-08-16T04:22:32Z

While we could do without this, extension code and third-party headers
are increasingly pulling this in, creating possible complications.  One,
bool defined in stdbool.h is not necessarily one byte in size.  Two, it
can only contain values 0 or 1 on output.  So having multiple
definitions of bool in play depending on include file order could create
a mess.

So we just get on board with this and use stdbool.h always if available.

As a benefit, some recent compilers can give some better warnings if the
official bool type is used.
---
 configure                  | 213 ++++++++++++++++++++++++++++++++++++---------
 configure.in               |   7 ++
 src/include/c.h            |  10 ++-
 src/include/pg_config.h.in |   9 ++
 src/pl/plperl/plperl.h     |  10 +--
 5 files changed, 202 insertions(+), 47 deletions(-)

diff --git a/configure b/configure
index d9b7b8d7ec..36f5550720 100755
--- a/configure
+++ b/configure
@@ -1996,116 +1996,116 @@ $as_echo "$ac_res" >&6; }
 
 } # ac_fn_c_check_func
 
-# 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_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_compute_int LINENO EXPR VAR INCLUDES
 # --------------------------------------------
@@ -10683,6 +10683,100 @@ 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
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
@@ -12861,6 +12955,43 @@ if test "$ac_cv_sizeof_off_t" -lt 8 -a "$segsize" != "1"; then
    as_fn_error $? "Large file support is not enabled. Segment size cannot be larger than 1GB." "$LINENO" 5
 fi
 
+# The cast to long int works around a bug in the HP C Compiler
+# version HP92453-01 B.11.11.23709.GP, which incorrectly rejects
+# declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'.
+# This bug is HP SR number 8606223364.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking size of bool" >&5
+$as_echo_n "checking size of bool... " >&6; }
+if ${ac_cv_sizeof_bool+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (bool))" "ac_cv_sizeof_bool"        "#ifdef HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+"; then :
+
+else
+  if test "$ac_cv_type_bool" = yes; then
+     { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 77 "cannot compute sizeof (bool)
+See \`config.log' for more details" "$LINENO" 5; }
+   else
+     ac_cv_sizeof_bool=0
+   fi
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sizeof_bool" >&5
+$as_echo "$ac_cv_sizeof_bool" >&6; }
+
+
+
+cat >>confdefs.h <<_ACEOF
+#define SIZEOF_BOOL $ac_cv_sizeof_bool
+_ACEOF
+
+
+
 
 ##
 ## Functions, global variables
diff --git a/configure.in b/configure.in
index 5245899109..fd03711176 100644
--- a/configure.in
+++ b/configure.in
@@ -1149,6 +1149,8 @@ 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])
 
 # On BSD, test for net/if.h will fail unless sys/socket.h
@@ -1407,6 +1409,11 @@ if test "$ac_cv_sizeof_off_t" -lt 8 -a "$segsize" != "1"; then
    AC_MSG_ERROR([Large file support is not enabled. Segment size cannot be larger than 1GB.])
 fi
 
+AC_CHECK_SIZEOF([bool], [],
+[#ifdef HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif])
+
 
 ##
 ## Functions, global variables
diff --git a/src/include/c.h b/src/include/c.h
index 1d656e37d5..e9cf1a7ee4 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -247,14 +247,20 @@
  * bool
  *		Boolean value, either true or false.
  *
- * XXX for C++ compilers, we assume the compiler has a compatible
+ * Use stdbool.h if available, to ensure best compatibility with third-party
+ * libraries.  For C++ compilers, we assume the compiler has a compatible
  * built-in definition of bool.
  */
 
 #ifndef __cplusplus
 
+#ifdef HAVE_STDBOOL_H
+#include <stdbool.h>
+#else
+
 #ifndef bool
 typedef char bool;
+#undef SIZEOF_BOOL
 #define SIZEOF_BOOL 1
 #endif
 
@@ -266,6 +272,8 @@ typedef char bool;
 #define false	((bool) 0)
 #endif
 
+#endif							/* not HAVE_STDBOOL_H */
+
 #endif							/* not C++ */
 
 /*
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 0aa6be4666..b7d00d4164 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -479,6 +479,9 @@
 /* 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. */
+#undef HAVE_STDBOOL_H
+
 /* Define to 1 if you have the <stdint.h> header file. */
 #undef HAVE_STDINT_H
 
@@ -678,6 +681,9 @@
 /* Define to 1 if you have the <winldap.h> header file. */
 #undef HAVE_WINLDAP_H
 
+/* 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
 
@@ -787,6 +793,9 @@
    RELSEG_SIZE requires an initdb. */
 #undef RELSEG_SIZE
 
+/* The size of `bool', as computed by sizeof. */
+#undef SIZEOF_BOOL
+
 /* The size of `long', as computed by sizeof. */
 #undef SIZEOF_LONG
 
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index aac95f8d2c..d8030398de 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -50,6 +50,11 @@
 #define __inline__ inline
 #endif
 
+/*
+ * Prevent perl from redefining "bool".
+ */
+#define HAS_BOOL 1
+
 
 /*
  * Get the basic Perl API.  We use PERL_NO_GET_CONTEXT mode so that our code
@@ -91,11 +96,6 @@
 #define NEED_sv_2pv_flags
 #include "ppport.h"
 
-/* perl may have a different width of "bool", don't buy it */
-#ifdef bool
-#undef bool
-#endif
-
 /* supply HeUTF8 if it's missing - ppport.h doesn't supply it, unfortunately */
 #ifndef HeUTF8
 #define HeUTF8(he)			   ((HeKLEN(he) == HEf_SVKEY) ?			   \
-- 
2.15.1


--------------AB99891BACB265862555DF3C--