2 dnl Copyright (C) 2008-2017 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 strstr works.
8 AC_DEFUN([gl_FUNC_STRSTR_SIMPLE],
10 AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
11 AC_REQUIRE([gl_FUNC_MEMCHR])
12 if test $HAVE_MEMCHR = 0 || test $REPLACE_MEMCHR = 1; then
15 dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
16 AC_CACHE_CHECK([whether strstr works],
17 [gl_cv_func_strstr_works_always],
18 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
19 #include <string.h> /* for strstr */
21 #define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
22 #define NEEDLE P P P P P
23 ]], [[return !!strstr (HAYSTACK, NEEDLE);
25 [gl_cv_func_strstr_works_always=yes],
26 [gl_cv_func_strstr_works_always=no],
27 [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. uClibc is not
28 dnl affected, since it uses different source code for strstr than
30 dnl Assume that it works on all other platforms, even if it is not
32 AC_EGREP_CPP([Lucky user],
34 #ifdef __GNU_LIBRARY__
36 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
40 #elif defined __CYGWIN__
41 #include <cygwin/version.h>
42 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
49 [gl_cv_func_strstr_works_always="guessing yes"],
50 [gl_cv_func_strstr_works_always="guessing no"])
53 case "$gl_cv_func_strstr_works_always" in
60 ]) # gl_FUNC_STRSTR_SIMPLE
62 dnl Additionally, check that strstr is efficient.
63 AC_DEFUN([gl_FUNC_STRSTR],
65 AC_REQUIRE([gl_FUNC_STRSTR_SIMPLE])
66 if test $REPLACE_STRSTR = 0; then
67 AC_CACHE_CHECK([whether strstr works in linear time],
68 [gl_cv_func_strstr_linear],
69 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
71 /* z/OS does not deliver signals while strstr() is running (thanks to
72 restrictions on its LE runtime), which prevents us from limiting the
73 running time of this test. */
74 # error "This test does not work properly on z/OS"
76 #include <signal.h> /* for signal */
77 #include <string.h> /* for strstr */
78 #include <stdlib.h> /* for malloc */
79 #include <unistd.h> /* for alarm */
80 static void quit (int sig) { _exit (sig + 128); }
84 char *haystack = (char *) malloc (2 * m + 2);
85 char *needle = (char *) malloc (m + 2);
86 /* Failure to compile this test due to missing alarm is okay,
87 since all such platforms (mingw) also have quadratic strstr. */
88 signal (SIGALRM, quit);
90 /* Check for quadratic performance. */
91 if (haystack && needle)
93 memset (haystack, 'A', 2 * m);
94 haystack[2 * m] = 'B';
95 haystack[2 * m + 1] = 0;
96 memset (needle, 'A', m);
99 if (!strstr (haystack, needle))
102 /* Free allocated memory, in case some sanitizer is watching. */
107 [gl_cv_func_strstr_linear=yes], [gl_cv_func_strstr_linear=no],
108 [dnl Only glibc > 2.12 on processors without SSE 4.2 instructions and
109 dnl cygwin > 1.7.7 are known to have a bug-free strstr that works in
111 AC_EGREP_CPP([Lucky user],
113 #include <features.h>
114 #ifdef __GNU_LIBRARY__
115 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
116 && !(defined __i386__ || defined __x86_64__) \
117 && !defined __UCLIBC__
122 #include <cygwin/version.h>
123 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
128 [gl_cv_func_strstr_linear="guessing yes"],
129 [gl_cv_func_strstr_linear="guessing no"])
132 case "$gl_cv_func_strstr_linear" in