1 # strcasestr.m4 serial 23
2 dnl Copyright (C) 2005, 2007-2017 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 $HAVE_MEMCHR = 0 || test $REPLACE_MEMCHR = 1; then
23 dnl Detect https://sourceware.org/bugzilla/show_bug.cgi?id=12092.
24 AC_CACHE_CHECK([whether strcasestr works],
25 [gl_cv_func_strcasestr_works_always],
26 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
27 #include <string.h> /* for strcasestr */
29 #define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
30 #define NEEDLE P P P P P
31 ]], [[return !!strcasestr (HAYSTACK, NEEDLE);
33 [gl_cv_func_strcasestr_works_always=yes],
34 [gl_cv_func_strcasestr_works_always=no],
35 [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. uClibc is not
36 dnl affected, since it uses different source code for strcasestr
38 dnl Assume that it works on all other platforms, even if it is not
40 AC_EGREP_CPP([Lucky user],
42 #ifdef __GNU_LIBRARY__
44 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
48 #elif defined __CYGWIN__
49 #include <cygwin/version.h>
50 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
57 [gl_cv_func_strcasestr_works_always="guessing yes"],
58 [gl_cv_func_strcasestr_works_always="guessing no"])
61 case "$gl_cv_func_strcasestr_works_always" in
69 ]) # gl_FUNC_STRCASESTR_SIMPLE
71 dnl Additionally, check that strcasestr is efficient.
72 AC_DEFUN([gl_FUNC_STRCASESTR],
74 AC_REQUIRE([gl_FUNC_STRCASESTR_SIMPLE])
75 if test $HAVE_STRCASESTR = 1 && test $REPLACE_STRCASESTR = 0; then
76 AC_CACHE_CHECK([whether strcasestr works in linear time],
77 [gl_cv_func_strcasestr_linear],
78 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
79 #include <signal.h> /* for signal */
80 #include <string.h> /* for strcasestr */
81 #include <stdlib.h> /* for malloc */
82 #include <unistd.h> /* for alarm */
83 static void quit (int sig) { _exit (sig + 128); }
87 char *haystack = (char *) malloc (2 * m + 2);
88 char *needle = (char *) malloc (m + 2);
89 /* Failure to compile this test due to missing alarm is okay,
90 since all such platforms (mingw) also lack strcasestr. */
91 signal (SIGALRM, quit);
93 /* Check for quadratic performance. */
94 if (haystack && needle)
96 memset (haystack, 'A', 2 * m);
97 haystack[2 * m] = 'B';
98 haystack[2 * m + 1] = 0;
99 memset (needle, 'A', m);
102 if (!strcasestr (haystack, needle))
105 /* Free allocated memory, in case some sanitizer is watching. */
110 [gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
111 [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
112 dnl strcasestr that works in linear time.
113 AC_EGREP_CPP([Lucky user],
115 #include <features.h>
116 #ifdef __GNU_LIBRARY__
117 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
118 && !defined __UCLIBC__
123 #include <cygwin/version.h>
124 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
129 [gl_cv_func_strcasestr_linear="guessing yes"],
130 [gl_cv_func_strcasestr_linear="guessing no"])
133 case "$gl_cv_func_strcasestr_linear" in
140 ]) # gl_FUNC_STRCASESTR
142 # Prerequisites of lib/strcasestr.c.
143 AC_DEFUN([gl_PREREQ_STRCASESTR], [