Re: fnmatch improvements

[Bruno Haible <bruno@clisp.org>]

Corinna Vinschen wrote:
> > >   4. cd testdir-fnmatch-posix
> > >      ./configure 2>&1 | tee log1
> > >      make
> > >      make check
> 
> I fixed the above problem and the POSIX check now works fine:

Glad that the test suite was helpful (and that you fixed it before 3.5.0 —
so, no additional configure tests needed on the gnulib side).

> > >      grep fnmatch log1
> 
>     checking for fnmatch.h... yes
>     checking for fnmatch... yes
>     checking for working POSIX fnmatch... yes
>
> I also extraced the fnmatch configure testcase and ran it manually.
> It returns 0 now.  But:
> 
> > >      grep REPLACE_FNMATCH config.status
> 
>     S["REPLACE_FNMATCH"]="1"
>
> Looks like the reason is that we don't have a uchar.h file?  Seems 
> like this is of interest for AIX, but why should this be of
> interest for fnmatch on other systems?

Ah, that's because I made the assumption that if wchar_t is only 16-bits
wide, fnmatch() can't be correct. Which is true for AIX (and on this
platform, I prefer not to test the available locales). But not true
with your implementation any more.

What are the test suite results if you do

  - Replace S["REPLACE_FNMATCH"]="1" with S["REPLACE_FNMATCH"]="0"
    in config.status,
  - make clean
  - ./config.status
  - make
  - make check

Then the tests will be run against Cygwin's fnmatch() function.
If all tests pass, I will add the following patch to gnulib.

diff --git a/m4/fnmatch.m4 b/m4/fnmatch.m4
index 2e1442eff7..e99737a476 100644
--- a/m4/fnmatch.m4
+++ b/m4/fnmatch.m4
@@ -1,4 +1,4 @@
-# Check for fnmatch - serial 18  -*- coding: utf-8 -*-
+# Check for fnmatch - serial 19  -*- coding: utf-8 -*-
 
 # Copyright (C) 2000-2007, 2009-2023 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -14,7 +14,7 @@ AC_DEFUN([gl_FUNC_FNMATCH_POSIX]
   m4_divert_text([DEFAULTS], [gl_fnmatch_required=POSIX])
 
   AC_REQUIRE([gl_FNMATCH_H])
-  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([AC_CANONICAL_HOST])
   gl_fnmatch_required_lowercase=`
     echo $gl_fnmatch_required | LC_ALL=C tr '[[A-Z]]' '[[a-z]]'
   `
@@ -164,7 +164,17 @@ AC_DEFUN([gl_FUNC_FNMATCH_POSIX]
     dnl This is due to wchar_t being only 16 bits wide.
     AC_REQUIRE([gl_UCHAR_H])
     if test $SMALL_WCHAR_T = 1; then
-      REPLACE_FNMATCH=1
+      case "$host_os" in
+        cygwin*)
+          dnl On Cygwin < 3.5.0, the above $gl_fnmatch_result came out as 'no',
+          dnl On Cygwin >= 3.5.0, fnmatch supports all Unicode characters,
+          dnl despite wchar_t being only 16 bits wide (because internally it
+          dnl works on wint_t values).
+          ;;
+        *)
+          REPLACE_FNMATCH=1
+          ;;
+      esac
     fi
   fi
   if test $HAVE_FNMATCH = 0 || test $REPLACE_FNMATCH = 1; then