1 # strcasestr.m4 serial 17
2 dnl Copyright (C) 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 dnl Check that strcasestr is present and works.
8 AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
10 AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
12 dnl Persuade glibc <string.h> to declare strcasestr().
13 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
15 AC_REQUIRE([gl_FUNC_MEMCHR])
16 AC_CHECK_FUNCS([strcasestr])
17 if test $ac_cv_func_strcasestr = no; then
20 if test "$gl_cv_func_memchr_works" != yes; then
23 dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
24 AC_CACHE_CHECK([whether strcasestr works],
25 [gl_cv_func_strcasestr_works_always],
26 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
27 #include <string.h> /* for strcasestr */
29 #define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
30 #define NEEDLE P P P P P
31 ]], [[return !!strcasestr (HAYSTACK, NEEDLE);
33 [gl_cv_func_strcasestr_works_always=yes],
34 [gl_cv_func_strcasestr_works_always=no],
35 [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. Assume that it
36 dnl works on all other platforms, even if it is not linear.
37 AC_EGREP_CPP([Lucky user],
39 #ifdef __GNU_LIBRARY__
41 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
42 && !defined __UCLIBC__
45 #elif defined __CYGWIN__
46 #include <cygwin/version.h>
47 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
54 [gl_cv_func_strcasestr_works_always=yes],
55 [gl_cv_func_strcasestr_works_always="guessing no"])
58 if test "$gl_cv_func_strcasestr_works_always" != yes; then
60 AC_LIBOBJ([strcasestr])
64 if test $HAVE_STRCASESTR = 0 || test $REPLACE_STRCASESTR = 1; then
65 AC_LIBOBJ([strcasestr])
68 ]) # gl_FUNC_STRCASESTR_SIMPLE
70 dnl Additionally, check that strcasestr is efficient.
71 AC_DEFUN([gl_FUNC_STRCASESTR],
73 AC_REQUIRE([gl_FUNC_STRCASESTR_SIMPLE])
74 if test $HAVE_STRCASESTR = 1 && test $REPLACE_STRCASESTR = 0; then
75 AC_CACHE_CHECK([whether strcasestr works in linear time],
76 [gl_cv_func_strcasestr_linear],
77 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
78 #include <signal.h> /* for signal */
79 #include <string.h> /* for strcasestr */
80 #include <stdlib.h> /* for malloc */
81 #include <unistd.h> /* for alarm */
82 static void quit (int sig) { exit (sig + 128); }
83 ]], [[size_t m = 1000000;
84 char *haystack = (char *) malloc (2 * m + 2);
85 char *needle = (char *) malloc (m + 2);
87 /* Failure to compile this test due to missing alarm is okay,
88 since all such platforms (mingw) also lack strcasestr. */
89 signal (SIGALRM, quit);
91 /* Check for quadratic performance. */
92 if (haystack && needle)
94 memset (haystack, 'A', 2 * m);
95 haystack[2 * m] = 'B';
96 haystack[2 * m + 1] = 0;
97 memset (needle, 'A', m);
100 result = strcasestr (haystack, needle);
103 [gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
104 [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
105 dnl strcasestr that works in linear time.
106 AC_EGREP_CPP([Lucky user],
108 #include <features.h>
109 #ifdef __GNU_LIBRARY__
110 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
111 && !defined __UCLIBC__
116 #include <cygwin/version.h>
117 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
122 [gl_cv_func_strcasestr_linear=yes],
123 [gl_cv_func_strcasestr_linear="guessing no"])
126 if test "$gl_cv_func_strcasestr_linear" != yes; then
128 AC_LIBOBJ([strcasestr])
132 ]) # gl_FUNC_STRCASESTR
134 # Prerequisites of lib/strcasestr.c.
135 AC_DEFUN([gl_PREREQ_STRCASESTR], [