[Bug-gnulib] new module "restrict", to fix a porting bug with regex

[Paul Eggert]

Here's a proposed new module "restrict".  It fixes a porting bug with
lib/regex.h on some platforms that lack "restrict", or spell it in
some other way.  The basic idea is taken from coreutils but I've
changed the name to gl_C_RESTRICT from ACX_C_RESTRICT.  We can remove
gl_C_RESTRICT later, after we assume Autoconf 2.57a or later.


--- ChangeLog.~1.70.~   Tue Aug  5 20:52:46 2003
+++ ChangeLog   Tue Aug  5 23:44:48 2003
@@ -1,5 +1,9 @@
 2003-08-05  Paul Eggert  <address@hidden>
 
+       * modules/restrict, m4/restrict.m4: New files.
+       * MODULES.html.sh (func_all_modules): Add restrict.
+       * modules/regex: Depend on restrict.
+       
        * MODULES.html.sh (func_all_modules): Remove bumpalloc.
        * modules/bumpalloc: Remove.
        
Index: m4/ChangeLog
===================================================================
RCS file: /cvsroot/gnulib/gnulib/m4/ChangeLog,v
retrieving revision 1.468
diff -p -u -r1.468 ChangeLog
--- m4/ChangeLog        6 Aug 2003 06:32:34 -0000       1.468
+++ m4/ChangeLog        6 Aug 2003 06:38:58 -0000
@@ -1,5 +1,7 @@
 2003-08-05  Paul Eggert  <address@hidden>
 
+       * regex.m4 (jm_PREREQ_REGEX): Add gl_C_RESTRICT.
+
        * regex.m4 (jm_INCLUDED_REGEX): Replace a single non-ASCII
        byte with "\201" to avoid glitches when editing that source file
        with multi-gnome-terminal.
--- /dev/null   Tue Mar 18 13:55:57 2003
+++ modules/restrict    Tue Aug  5 22:53:30 2003
@@ -0,0 +1,17 @@
+Description:
+The C99 'restrict' keyword.
+
+Files:
+m4/restrict.m4
+
+Depends-on:
+
+configure.ac:
+gl_C_RESTRICT
+
+Makefile.am:
+
+Include:
+
+Maintainer:
+Paul Eggert and Jim Meyering
--- /dev/null   Tue Mar 18 13:55:57 2003
+++ m4/restrict.m4      Tue Aug  5 22:52:43 2003
@@ -0,0 +1,33 @@
+#serial 1002
+# This macro can be removed once we can rely on Autoconf 2.57a or later,
+# since we can then use its AC_C_RESTRICT.
+
+# gl_C_RESTRICT
+# --------------
+# Determine whether the C/C++ compiler supports the "restrict" keyword
+# introduced in ANSI C99, or an equivalent.  Do nothing if the compiler
+# accepts it.  Otherwise, if the compiler supports an equivalent,
+# define "restrict" to be that.  Here are some variants:
+# - GCC supports both __restrict and __restrict__
+# - older DEC Alpha C compilers support only __restrict
+# - _Restrict is the only spelling accepted by Sun WorkShop 6 update 2 C
+# Otherwise, define "restrict" to be empty.
+AC_DEFUN([gl_C_RESTRICT],
+[AC_CACHE_CHECK([for C/C++ restrict keyword], gl_cv_c_restrict,
+  [gl_cv_c_restrict=no
+   # Try the official restrict keyword, then gcc's __restrict, and
+   # the less common variants.
+   for ac_kw in restrict __restrict __restrict__ _Restrict; do
+     AC_COMPILE_IFELSE([AC_LANG_SOURCE(
+      [float * $ac_kw x;])],
+      [gl_cv_c_restrict=$ac_kw; break])
+   done
+  ])
+ case $gl_cv_c_restrict in
+   restrict) ;;
+   no) AC_DEFINE(restrict,,
+       [Define to equivalent of C99 restrict keyword, or to nothing if this
+       is not supported.  Do not define if restrict is supported directly.]) ;;
+   *)  AC_DEFINE_UNQUOTED(restrict, $gl_cv_c_restrict) ;;
+ esac
+])
Index: MODULES.html.sh
===================================================================
RCS file: /cvsroot/gnulib/gnulib/MODULES.html.sh,v
retrieving revision 1.30
diff -p -u -r1.30 MODULES.html.sh
--- MODULES.html.sh     6 Aug 2003 03:52:46 -0000       1.30
+++ MODULES.html.sh     6 Aug 2003 06:38:54 -0000
@@ -1593,6 +1593,16 @@ func_all_modules ()
   func_wrap H2
   func_echo "$element"
 
+  element="Keywords"
+  element=`printf "%s" "$element" | sed -e "$sed_lt" -e "$sed_gt"`
+  func_section_wrap isoc_sup_keywords
+  func_wrap H3
+  func_echo "$element"
+
+  func_begin_table
+  func_module restrict
+  func_end_table
+
   element="Boolean type and values <stdbool.h>"
   element=`printf "%s" "$element" | sed -e "$sed_lt" -e "$sed_gt"`
   func_section_wrap isoc_sup_stdbool
Index: m4/regex.m4
===================================================================
RCS file: /cvsroot/gnulib/gnulib/m4/regex.m4,v
retrieving revision 1.33
diff -p -u -r1.33 regex.m4
--- m4/regex.m4 6 Aug 2003 06:27:39 -0000       1.33
+++ m4/regex.m4 6 Aug 2003 06:38:58 -0000
@@ -1,4 +1,4 @@
-#serial 17
+#serial 18
 
 dnl Initially derived from code in GNU grep.
 dnl Mostly written by Jim Meyering.
@@ -110,6 +110,7 @@ AC_DEFUN([jm_PREREQ_REGEX],
   dnl Persuade glibc <string.h> to declare mempcpy().
   AC_REQUIRE([AC_GNU_SOURCE])
 
+  AC_REQUIRE([gl_C_RESTRICT])
   AC_REQUIRE([AC_FUNC_ALLOCA])
   AC_REQUIRE([AC_HEADER_STDC])
   AC_CHECK_HEADERS_ONCE(limits.h string.h wchar.h wctype.h)
Index: modules/regex
===================================================================
RCS file: /cvsroot/gnulib/gnulib/modules/regex,v
retrieving revision 1.3
diff -p -u -r1.3 regex
--- modules/regex       20 Jan 2003 10:02:38 -0000      1.3
+++ modules/regex       6 Aug 2003 06:38:58 -0000
@@ -8,6 +8,7 @@ m4/regex.m4
 
 Depends-on:
 alloca
+restrict
 unlocked-io
 gettext