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# strcasestr.m4 serial 13
dnl Copyright (C) 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl Check that strcasestr is present and works.
AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
[
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
dnl Persuade glibc <string.h> to declare strcasestr().
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
AC_REQUIRE([gl_FUNC_MEMCHR])
AC_CHECK_FUNCS([strcasestr])
if test $ac_cv_func_strcasestr = no; then
HAVE_STRCASESTR=0
else
if test "$gl_cv_func_memchr_works" != yes; then
REPLACE_STRCASESTR=1
fi
fi
if test $HAVE_STRCASESTR = 0 || test $REPLACE_STRCASESTR = 1; then
AC_LIBOBJ([strcasestr])
gl_PREREQ_STRCASESTR
fi
]) # gl_FUNC_STRCASESTR_SIMPLE
dnl Additionally, check that strcasestr is efficient.
AC_DEFUN([gl_FUNC_STRCASESTR],
[
AC_REQUIRE([gl_FUNC_STRCASESTR_SIMPLE])
if test $HAVE_STRCASESTR = 1 && test $REPLACE_STRCASESTR = 0; then
AC_CACHE_CHECK([whether strcasestr works in linear time],
[gl_cv_func_strcasestr_linear],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <signal.h> /* for signal */
#include <string.h> /* for memmem */
#include <stdlib.h> /* for malloc */
#include <unistd.h> /* for alarm */
]], [[size_t m = 1000000;
char *haystack = (char *) malloc (2 * m + 2);
char *needle = (char *) malloc (m + 2);
void *result = 0;
/* Failure to compile this test due to missing alarm is okay,
since all such platforms (mingw) also lack strcasestr. */
signal (SIGALRM, SIG_DFL);
alarm (5);
/* Check for quadratic performance. */
if (haystack && needle)
{
memset (haystack, 'A', 2 * m);
haystack[2 * m] = 'B';
haystack[2 * m + 1] = 0;
memset (needle, 'A', m);
needle[m] = 'B';
needle[m + 1] = 0;
result = strcasestr (haystack, needle);
}
return !result;]])],
[gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
[dnl Only glibc >= 2.9 and cygwin >= 1.7.0 are known to have a
dnl strcasestr that works in linear time.
AC_EGREP_CPP([Lucky user],
[
#include <features.h>
#ifdef __GNU_LIBRARY__
#if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2)
Lucky user
#endif
#endif
#ifdef __CYGWIN__
#include <cygwin/version.h>
#if CYGWIN_VERSION_DLL_MAJOR >= 1007
Lucky user
#endif
#endif
],
[gl_cv_func_strcasestr_linear=yes],
[gl_cv_func_strcasestr_linear="guessing no"])
])
])
if test "$gl_cv_func_strcasestr_linear" != yes; then
REPLACE_STRCASESTR=1
AC_LIBOBJ([strcasestr])
gl_PREREQ_STRCASESTR
fi
fi
]) # gl_FUNC_STRCASESTR
# Prerequisites of lib/strcasestr.c.
AC_DEFUN([gl_PREREQ_STRCASESTR], [
:
])
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