1 # strcasestr.m4 serial 16
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)
44 #elif defined __CYGWIN__
45 #include <cygwin/version.h>
46 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
53 [gl_cv_func_strcasestr_works_always=yes],
54 [gl_cv_func_strcasestr_works_always="guessing no"])
57 if test "$gl_cv_func_strcasestr_works_always" != yes; then
59 AC_LIBOBJ([strcasestr])
63 if test $HAVE_STRCASESTR = 0 || test $REPLACE_STRCASESTR = 1; then
64 AC_LIBOBJ([strcasestr])
67 ]) # gl_FUNC_STRCASESTR_SIMPLE
69 dnl Additionally, check that strcasestr is efficient.
70 AC_DEFUN([gl_FUNC_STRCASESTR],
72 AC_REQUIRE([gl_FUNC_STRCASESTR_SIMPLE])
73 if test $HAVE_STRCASESTR = 1 && test $REPLACE_STRCASESTR = 0; then
74 AC_CACHE_CHECK([whether strcasestr works in linear time],
75 [gl_cv_func_strcasestr_linear],
76 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
77 #include <signal.h> /* for signal */
78 #include <string.h> /* for strcasestr */
79 #include <stdlib.h> /* for malloc */
80 #include <unistd.h> /* for alarm */
81 static void quit (int sig) { exit (sig + 128); }
82 ]], [[size_t m = 1000000;
83 char *haystack = (char *) malloc (2 * m + 2);
84 char *needle = (char *) malloc (m + 2);
86 /* Failure to compile this test due to missing alarm is okay,
87 since all such platforms (mingw) also lack strcasestr. */
88 signal (SIGALRM, quit);
90 /* Check for quadratic performance. */
91 if (haystack && needle)
93 memset (haystack, 'A', 2 * m);
94 haystack[2 * m] = 'B';
95 haystack[2 * m + 1] = 0;
96 memset (needle, 'A', m);
99 result = strcasestr (haystack, needle);
102 [gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
103 [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
104 dnl strcasestr that works in linear time.
105 AC_EGREP_CPP([Lucky user],
107 #include <features.h>
108 #ifdef __GNU_LIBRARY__
109 #if (__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)
114 #include <cygwin/version.h>
115 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
120 [gl_cv_func_strcasestr_linear=yes],
121 [gl_cv_func_strcasestr_linear="guessing no"])
124 if test "$gl_cv_func_strcasestr_linear" != yes; then
126 AC_LIBOBJ([strcasestr])
130 ]) # gl_FUNC_STRCASESTR
132 # Prerequisites of lib/strcasestr.c.
133 AC_DEFUN([gl_PREREQ_STRCASESTR], [