Subject: Re: [PATCH/RFC v2 0/3] Update compat/regex

From: Jonathan Nieder <[email-masked]>
Date: Tue, 17 Aug 2010 03:03:22 -0500

Ævar Arnfjörð Bjarmason wrote:

> Ævar Arnfjörð Bjarmason (3):
>   compat/regex: use the regex engine from gawk for compat
>   compat/regex: get the gawk regex engine to compile within git
>   t/t7008-grep-binary.sh: un-TODO a test that needs REG_STARTEND

For what it’s worth:

Acked-by: Jonathan Nieder <[email-masked]>

Thanks.  Here’s a patch to go on top.  I am not sure what platforms
support REG_STARTEND, but we can always update the makefile as reports
come in.

-- 8< --
Subject: autoconf: don't use platform regex if it lacks REG_STARTEND

If the platform regex cannot match null bytes, we might as well
use the glibc version instead.

Cc: Ævar Arnfjörð Bjarmason <[email-masked]>
Cc: René Scharfe <[email-masked]>
Signed-off-by: Jonathan Nieder <[email-masked]>
---
 config.mak.in |    1 +
 configure.ac  |   21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/config.mak.in b/config.mak.in
index b4e65c3..67dbd3b 100644
--- a/config.mak.in
+++ b/config.mak.in
@@ -58,6 +58,7 @@ NO_INET_NTOP=@NO_INET_NTOP@
 NO_INET_PTON=@NO_INET_PTON@
 NO_ICONV=@NO_ICONV@
 OLD_ICONV=@OLD_ICONV@
+NO_REGEX=@NO_REGEX@
 NO_DEFLATE_BOUND=@NO_DEFLATE_BOUND@
 INLINE=@INLINE@
 SOCKLEN_T=@SOCKLEN_T@
diff --git a/configure.ac b/configure.ac
index 5601e8b..71ac89f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -706,6 +706,27 @@ else
 fi
 AC_SUBST(NO_C99_FORMAT)
 #
+# Define NO_REGEX if you have no or inferior regex support in your C library.
+AC_CACHE_CHECK([whether the platform regex can handle null bytes],
+ [ac_cv_c_excellent_regex], [
+AC_EGREP_CPP(yippeeyeswehaveit,
+	AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT
+#include <regex.h>
+],
+[#ifdef REG_STARTEND
+yippeeyeswehaveit
+#endif
+]),
+	[ac_cv_c_excellent_regex=yes],
+	[ac_cv_c_excellent_regex=yes])
+])
+if test $ac_cv_c_excellent_regex = yes; then
+	NO_REGEX=
+else
+	NO_REGEX=YesPlease
+fi
+AC_SUBST(NO_REGEX)
+#
 # Define FREAD_READS_DIRECTORIES if your are on a system which succeeds
 # when attempting to read from an fopen'ed directory.
 AC_CACHE_CHECK([whether system succeeds to read fopen'ed directory],
-- 
1.7.2.1.544.ga752d.dirty