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[gnulib.git] / m4 / regex.m4
blob0017507edf03ecd43cbbae382ba785f0078b2dd7
1 #serial 12
3 dnl Initially derived from code in GNU grep.
4 dnl Mostly written by Jim Meyering.
6 dnl Usage: jm_INCLUDED_REGEX([lib/regex.c])
7 dnl
8 AC_DEFUN([jm_INCLUDED_REGEX],
9   [
10     dnl Even packages that don't use regex.c can use this macro.
11     dnl Of course, for them it doesn't do anything.
13     # Assume we'll default to using the included regex.c.
14     ac_use_included_regex=yes
16     # However, if the system regex support is good enough that it passes the
17     # the following run test, then default to *not* using the included regex.c.
18     # If cross compiling, assume the test would fail and use the included
19     # regex.c.  The first failing regular expression is from `Spencer ere
20     # test #75' in grep-2.3.
21     AC_CACHE_CHECK([for working re_compile_pattern],
22                    jm_cv_func_working_re_compile_pattern,
23       AC_TRY_RUN(
24 [#include <stdio.h>
25 #include <regex.h>
26           int
27           main ()
28           {
29             static struct re_pattern_buffer regex;
30             const char *s;
31             struct re_registers regs;
32             re_set_syntax (RE_SYNTAX_POSIX_EGREP);
33             [s = re_compile_pattern ("a[[:@:>@:]]b\n", 9, &regex);]
34             /* This should fail with _Invalid character class name_ error.  */
35             if (!s)
36               exit (1);
38             /* This should succeed, but doesn't for e.g. glibc-2.1.3.  */
39             s = re_compile_pattern ("{1", 2, &regex);
41             if (s)
42               exit (1);
44             /* The following example is derived from a problem report
45                against gawk from Jorge Stolfi <stolfi@ic.unicamp.br>.  */
46             s = re_compile_pattern ("[[anĂ¹]]*n", 7, &regex);
47             if (s)
48               exit (1);
50             /* This should match, but doesn't for e.g. glibc-2.2.1.  */
51             if (re_match (&regex, "an", 2, 0, &regs) != 2)
52               exit (1);
54             exit (0);
55           }
56         ],
57                jm_cv_func_working_re_compile_pattern=yes,
58                jm_cv_func_working_re_compile_pattern=no,
59                dnl When crosscompiling, assume it's broken.
60                jm_cv_func_working_re_compile_pattern=no))
61     if test $jm_cv_func_working_re_compile_pattern = yes; then
62       ac_use_included_regex=no
63     fi
65     test -n "$1" || AC_MSG_ERROR([missing argument])
66     m4_syscmd([test -f $1])
67     ifelse(m4_sysval, 0,
68       [
69         AC_ARG_WITH(included-regex,
70         [  --without-included-regex don't compile regex; this is the default on
71                           systems with version 2 of the GNU C library
72                           (use with caution on other system)],
73                     jm_with_regex=$withval,
74                     jm_with_regex=$ac_use_included_regex)
75         if test "$jm_with_regex" = yes; then
76           AC_LIBOBJ(regex)
77         fi
78       ],
79     )
80   ]