Re: glob on glibc systems

[Bruno Haible]

I wrote:
> This is because /usr/include/gnu-versions.h now defines
> _GNU_GLOB_INTERFACE_VERSION to 2, following this commit in glibc:
> https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=ccf970c7a77e86f4f5ef8ecc5e637114b1c0136a

The motivation of _GNU_GLOB_INTERFACE_VERSION == 2 being the new handling
of dangling symlinks, and this change being already in gnulib since 2017-08-31
http://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=commitdiff;h=fd1daf4e1824bb46c08ba6244b4d41c8cecb3642
it looks like gnulib's replacement is not needed when
_GNU_GLOB_INTERFACE_VERSION == 2. And indeed this patch works fine for me.
Tested on glibc 2.23, recent glibc, and mingw; including the C++ tests.
Pushed.


2018-03-16  Bruno Haible  <address@hidden>

        glob: Don't compile replacements on recent glibc systems.
        * lib/glob.in.h: Use the usual idiom for the double-inclusion guard. If
        REPLACE_GLOB is 0, include the system's <glob.h> and use
        _GL_CXXALIAS_SYS.
        * m4/glob.m4 (gl_GLOB): Set REPLACE_GLOB instead of GLOB_H. Accept
        _GNU_GLOB_INTERFACE_VERSION 2 as well. Delete the file conf$$-globtest
        inside the AC_RUN_IFELSE block. Remove GL_GENERATE_GLOB_H conditional.
        * modules/glob (Dependencies): Test REPLACE_GLOB instead of GLOB_H.
        Remove snippet/warn-on-use.
        (configure.ac): Test REPLACE_GLOB instead of GLOB_H.
        (Makefile.am): Create glob.h always. Update list of substitutions in
        glob.h. Don't depend on $(WARN_ON_USE_H).

diff --git a/lib/glob.in.h b/lib/glob.in.h
index cc3f48c..656c1eb 100644
--- a/lib/glob.in.h
+++ b/lib/glob.in.h
@@ -17,21 +17,22 @@
    You should have received a copy of the GNU General Public License
    along with this program; if not, see <https://www.gnu.org/licenses/>.  */
 
-#ifndef _GL_GLOB_H
-#define _GL_GLOB_H
+#ifndef address@hidden@_GLOB_H
 
-#include <libc-config.h>
+#if __GNUC__ >= 3
address@hidden@
+#endif
address@hidden@
 
-#include <stddef.h>
+/* The include_next requires a split double-inclusion guard.  */
+#if address@hidden@
+# @INCLUDE_NEXT@ @NEXT_GLOB_H@
+#endif
 
-/* On some systems, such as AIX 5.1, <sys/stat.h> does a "#define stat stat64".
-   Make sure this definition is seen before glob-libc.h defines types that
-   rely on 'struct stat'.  */
-#include <sys/stat.h>
+#ifndef address@hidden@_GLOB_H
+#define address@hidden@_GLOB_H
 
-#ifndef __USE_GNU
-# define __USE_GNU    1
-#endif
+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
 
 /* GCC 2.95 and later have "__restrict"; C99 compilers have
    "restrict", and "configure" may have defined "restrict".
@@ -48,35 +49,71 @@
 # endif
 #endif
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+typedef int (*_gl_glob_errfunc_fn) (const char *, int);
+#ifdef __cplusplus
+}
+#endif
+
+
+#if @REPLACE_GLOB@
+
+
+/* Preparations for including the standard GNU C Library header.  */
+
+# include <libc-config.h>
+
+# include <stddef.h>
+
+/* On some systems, such as AIX 5.1, <sys/stat.h> does a "#define stat stat64".
+   Make sure this definition is seen before glob-libc.h defines types that
+   rely on 'struct stat'.  */
+# include <sys/stat.h>
+
+# ifndef __USE_GNU
+#  define __USE_GNU    1
+# endif
+
+# define glob rpl_glob
+# define globfree rpl_globfree
+# define glob_pattern_p rpl_glob_pattern_p
+# define __glob_pattern_p glob_pattern_p
 
-#define glob rpl_glob
-#define globfree rpl_globfree
-#define glob_pattern_p rpl_glob_pattern_p
-#define __glob_pattern_p glob_pattern_p
+# define __GLOB_GNULIB 1
 
-#define __GLOB_GNULIB 1
 
 /* Now the standard GNU C Library header should work.  */
-#include "glob-libc.h"
+# include "glob-libc.h"
 
-__BEGIN_DECLS
-typedef int (*_gl_glob_errfunc_fn) (const char *, int);
-__END_DECLS
 
-#if defined __cplusplus && defined GNULIB_NAMESPACE
-# undef glob
-# undef globfree
-# undef glob_pattern_p
+# if defined __cplusplus && defined GNULIB_NAMESPACE
+#  undef glob
+#  undef globfree
+#  undef glob_pattern_p
 _GL_CXXALIAS_RPL (glob, int, (const char *_Restrict_ __pattern, int __flags,
                               _gl_glob_errfunc_fn __errfunc,
                               glob_t *_Restrict_ __pglob));
 _GL_CXXALIAS_RPL (globfree, void, (glob_t *__pglob));
 _GL_CXXALIAS_RPL (glob_pattern_p, int, (const char *__pattern, int __quote));
-# if 0  /* The C function name is rpl_glob, not glob.  */
+# endif
+
+#else
+
+_GL_CXXALIAS_SYS (glob, int, (const char *_Restrict_ __pattern, int __flags,
+                              _gl_glob_errfunc_fn __errfunc,
+                              glob_t *_Restrict_ __pglob));
+_GL_CXXALIAS_SYS (globfree, void, (glob_t *__pglob));
+_GL_CXXALIAS_SYS (glob_pattern_p, int, (const char *__pattern, int __quote));
+
+#endif
+
+#if 0  /* The C function name is rpl_glob in some cases, not glob.  */
 _GL_CXXALIASWARN (glob);
 _GL_CXXALIASWARN (globfree);
 _GL_CXXALIASWARN (glob_pattern_p);
-# endif
 #endif
 
-#endif /* _GL_GLOB_H */
+#endif /* address@hidden@_GLOB_H */
+#endif /* address@hidden@_GLOB_H */
diff --git a/m4/glob.m4 b/m4/glob.m4
index 9dedb41..37cb917 100644
--- a/m4/glob.m4
+++ b/m4/glob.m4
@@ -1,4 +1,4 @@
-# glob.m4 serial 16
+# glob.m4 serial 18
 dnl Copyright (C) 2005-2007, 2009-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -9,54 +9,58 @@ dnl with or without modifications, as long as this notice is 
preserved.
 # always include <glob.h> for the glob prototypes.
 
 AC_DEFUN([gl_GLOB],
-[ GLOB_H=
-  AC_CHECK_HEADERS([glob.h], [], [GLOB_H=glob.h])
+[
+  dnl <glob.h> is always overridden, because of the C++ GNULIB_NAMESPACE.
+  gl_CHECK_NEXT_HEADERS([glob.h])
+  if test $ac_cv_header_glob_h = yes; then
+    REPLACE_GLOB=0
+  else
+    REPLACE_GLOB=1
+  fi
 
-  if test -z "$GLOB_H"; then
-    AC_CACHE_CHECK([for GNU glob interface version 1],
-      [gl_cv_gnu_glob_interface_version_1],
+  if test $REPLACE_GLOB = 0; then
+    AC_CACHE_CHECK([for GNU glob interface version 1 or 2],
+      [gl_cv_gnu_glob_interface_version_1_2],
 [     AC_COMPILE_IFELSE([AC_LANG_SOURCE(
 [[#include <gnu-versions.h>
-char a[_GNU_GLOB_INTERFACE_VERSION == 1 ? 1 : -1];]])],
-        [gl_cv_gnu_glob_interface_version_1=yes],
-        [gl_cv_gnu_glob_interface_version_1=no])])
+char a[_GNU_GLOB_INTERFACE_VERSION == 1 || _GNU_GLOB_INTERFACE_VERSION == 2 ? 
1 : -1];]])],
+        [gl_cv_gnu_glob_interface_version_1_2=yes],
+        [gl_cv_gnu_glob_interface_version_1_2=no])])
 
-    if test "$gl_cv_gnu_glob_interface_version_1" = "no"; then
-      GLOB_H=glob.h
+    if test "$gl_cv_gnu_glob_interface_version_1_2" = "no"; then
+      REPLACE_GLOB=1
     fi
   fi
 
-  if test -z "$GLOB_H"; then
+  if test $REPLACE_GLOB = 0; then
     AC_CACHE_CHECK([whether glob lists broken symlinks],
                    [gl_cv_glob_lists_symlinks],
-[     if ln -s conf-doesntexist conf$$-globtest 2>/dev/null; then
-        gl_cv_glob_lists_symlinks=maybe
-      else
-        # If we can't make a symlink, then we cannot test this issue.  Be
-        # pessimistic about this.
-        gl_cv_glob_lists_symlinks=no
-      fi
-
-      if test $gl_cv_glob_lists_symlinks = maybe; then
-        AC_RUN_IFELSE([
+      [if ln -s conf-doesntexist conf$$-globtest 2>/dev/null; then
+         gl_cv_glob_lists_symlinks=maybe
+       else
+         # If we can't make a symlink, then we cannot test this issue.  Be
+         # pessimistic about this.
+         gl_cv_glob_lists_symlinks=no
+       fi
+       if test $gl_cv_glob_lists_symlinks = maybe; then
+         AC_RUN_IFELSE([
 AC_LANG_PROGRAM(
 [[#include <stddef.h>
 #include <glob.h>]],
 [[glob_t found;
 if (glob ("conf*-globtest", 0, NULL, &found) == GLOB_NOMATCH) return 1;]])],
-          [gl_cv_glob_lists_symlinks=yes],
-          [gl_cv_glob_lists_symlinks=no], [gl_cv_glob_lists_symlinks=no])
-      fi])
+           [gl_cv_glob_lists_symlinks=yes],
+           [gl_cv_glob_lists_symlinks=no], [gl_cv_glob_lists_symlinks=no])
+       fi
+       rm -f conf$$-globtest
+      ])
 
     if test $gl_cv_glob_lists_symlinks = no; then
-      GLOB_H=glob.h
+      REPLACE_GLOB=1
     fi
   fi
 
-  rm -f conf$$-globtest
-
-  AC_SUBST([GLOB_H])
-  AM_CONDITIONAL([GL_GENERATE_GLOB_H], [test -n "$GLOB_H"])
+  AC_SUBST([REPLACE_GLOB])
 ])
 
 # Prerequisites of lib/glob.*.
diff --git a/modules/glob b/modules/glob
index 3a43222..94b3fd0 100644
--- a/modules/glob
+++ b/modules/glob
@@ -16,31 +16,30 @@ c99
 extensions
 largefile
 snippet/c++defs
-snippet/warn-on-use
-alloca          [test -n "$GLOB_H"]
-builtin-expect  [test -n "$GLOB_H"]
-closedir        [test -n "$GLOB_H"]
-d-type          [test -n "$GLOB_H"]
-flexmember      [test -n "$GLOB_H"]
-fnmatch         [test -n "$GLOB_H"]
-getlogin_r      [test -n "$GLOB_H"]
-libc-config     [test -n "$GLOB_H"]
-lstat           [test -n "$GLOB_H"]
-memchr          [test -n "$GLOB_H"]
-mempcpy         [test -n "$GLOB_H"]
-opendir         [test -n "$GLOB_H"]
-readdir         [test -n "$GLOB_H"]
-scratch_buffer  [test -n "$GLOB_H"]
-stdbool         [test -n "$GLOB_H"]
-stdint          [test -n "$GLOB_H"]
-strdup          [test -n "$GLOB_H"]
-sys_stat        [test -n "$GLOB_H"]
-unistd          [test -n "$GLOB_H"]
-malloc-posix    [test -n "$GLOB_H"]
+alloca          [test $REPLACE_GLOB = 1]
+builtin-expect  [test $REPLACE_GLOB = 1]
+closedir        [test $REPLACE_GLOB = 1]
+d-type          [test $REPLACE_GLOB = 1]
+flexmember      [test $REPLACE_GLOB = 1]
+fnmatch         [test $REPLACE_GLOB = 1]
+getlogin_r      [test $REPLACE_GLOB = 1]
+libc-config     [test $REPLACE_GLOB = 1]
+lstat           [test $REPLACE_GLOB = 1]
+memchr          [test $REPLACE_GLOB = 1]
+mempcpy         [test $REPLACE_GLOB = 1]
+opendir         [test $REPLACE_GLOB = 1]
+readdir         [test $REPLACE_GLOB = 1]
+scratch_buffer  [test $REPLACE_GLOB = 1]
+stdbool         [test $REPLACE_GLOB = 1]
+stdint          [test $REPLACE_GLOB = 1]
+strdup          [test $REPLACE_GLOB = 1]
+sys_stat        [test $REPLACE_GLOB = 1]
+unistd          [test $REPLACE_GLOB = 1]
+malloc-posix    [test $REPLACE_GLOB = 1]
 
 configure.ac:
 gl_GLOB
-if test -n "$GLOB_H"; then
+if test $REPLACE_GLOB = 1; then
   AC_LIBOBJ([glob])
   AC_LIBOBJ([glob_pattern_p])
   AC_LIBOBJ([globfree])
@@ -48,23 +47,22 @@ if test -n "$GLOB_H"; then
 fi
 
 Makefile.am:
-BUILT_SOURCES += $(GLOB_H)
+BUILT_SOURCES += glob.h
 
-# We need the following in order to create <glob.h> when the system
-# doesn't have one that works with the given compiler.
-if GL_GENERATE_GLOB_H
-glob.h: glob.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(WARN_ON_USE_H)
+# We need the following in order to create <glob.h>.
+glob.h: glob.in.h $(top_builddir)/config.status $(CXXDEFS_H)
        $(AM_V_GEN)rm -f address@hidden $@ && \
        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
-         sed -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
-             -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
+         sed -e 's|@''GUARD_PREFIX''@|${gl_include_guard_prefix}|g' \
+             -e 's|@''REPLACE_GLOB''@|$(REPLACE_GLOB)|g' \
+             -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
+             -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
+             -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
+             -e 's|@''NEXT_GLOB_H''@|$(NEXT_GLOB_H)|g' \
+             -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
              < $(srcdir)/glob.in.h; \
        } > address@hidden && \
        mv -f address@hidden $@
-else
-glob.h: $(top_builddir)/config.status
-       rm -f $@
-endif
 MOSTLYCLEANFILES += glob.h glob.h-t
 
 Include: