2 dnl Copyright (C) 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 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 "$gl_cv_func_memchr_works" != yes; then
16 dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
17 AC_CACHE_CHECK([whether strstr works],
18 [gl_cv_func_strstr_works_always],
19 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
20 #include <string.h> /* for strstr */
22 #define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
23 #define NEEDLE P P P P P
24 ]], [[return !!strstr (HAYSTACK, NEEDLE);
26 [gl_cv_func_strstr_works_always=yes],
27 [gl_cv_func_strstr_works_always=no],
28 [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. Assume that it
29 dnl works on all other platforms, even if it is not linear.
30 AC_EGREP_CPP([Lucky user],
32 #ifdef __GNU_LIBRARY__
34 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
35 && !defined __UCLIBC__
38 #elif defined __CYGWIN__
39 #include <cygwin/version.h>
40 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
47 [gl_cv_func_strstr_works_always=yes],
48 [gl_cv_func_strstr_works_always="guessing no"])
51 if test "$gl_cv_func_strstr_works_always" != yes; then
56 ]) # gl_FUNC_STRSTR_SIMPLE
58 dnl Additionally, check that strstr is efficient.
59 AC_DEFUN([gl_FUNC_STRSTR],
61 AC_REQUIRE([gl_FUNC_STRSTR_SIMPLE])
62 if test $REPLACE_STRSTR = 0; then
63 AC_CACHE_CHECK([whether strstr works in linear time],
64 [gl_cv_func_strstr_linear],
65 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
66 #include <signal.h> /* for signal */
67 #include <string.h> /* for strstr */
68 #include <stdlib.h> /* for malloc */
69 #include <unistd.h> /* for alarm */
70 static void quit (int sig) { exit (sig + 128); }
71 ]], [[size_t m = 1000000;
72 char *haystack = (char *) malloc (2 * m + 2);
73 char *needle = (char *) malloc (m + 2);
75 /* Failure to compile this test due to missing alarm is okay,
76 since all such platforms (mingw) also have quadratic strstr. */
77 signal (SIGALRM, quit);
79 /* Check for quadratic performance. */
80 if (haystack && needle)
82 memset (haystack, 'A', 2 * m);
83 haystack[2 * m] = 'B';
84 haystack[2 * m + 1] = 0;
85 memset (needle, 'A', m);
88 result = strstr (haystack, needle);
91 [gl_cv_func_strstr_linear=yes], [gl_cv_func_strstr_linear=no],
92 [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
93 dnl bug-free strstr that works in linear time.
94 AC_EGREP_CPP([Lucky user],
97 #ifdef __GNU_LIBRARY__
98 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
99 && !defined __UCLIBC__
104 #include <cygwin/version.h>
105 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
110 [gl_cv_func_strstr_linear=yes],
111 [gl_cv_func_strstr_linear="guessing no"])
114 if test "$gl_cv_func_strstr_linear" != yes; then
118 if test $REPLACE_STRSTR = 1; then