view m4/glibc21.m4 @ 9600:99268e709d31

Avoid quadratic strstr implementations. * lib/strstr.c: New file. * m4/strstr.m4: Likewise. * modules/strstr: Likewise. * modules/strstr-tests: Likewise. * tests/test-strstr.c: Likewise. * lib/string.in.h (rpl_strstr): Declare. (memmem) [GNULIB_POSIXCHECK]: Document speed issue. * m4/string_h.m4 (gl_HEADER_STRING_H_DEFAULTS): Support strstr. * modules/string (Makefile.am): Likewise. * MODULES.html.sh (string handling): Mention new module. * doc/functions/strstr.texi (strstr): Document the bug. Signed-off-by: Eric Blake <ebb9@byu.net>
author Eric Blake <ebb9@byu.net>
date Thu, 10 Jan 2008 07:38:11 -0700
parents adff74659d81
children 03e819eea554
line wrap: on
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# glibc21.m4 serial 3
dnl Copyright (C) 2000-2002, 2004 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.

# Test for the GNU C Library, version 2.1 or newer.
# From Bruno Haible.

AC_DEFUN([gl_GLIBC21],
  [
    AC_CACHE_CHECK(whether we are using the GNU C Library 2.1 or newer,
      ac_cv_gnu_library_2_1,
      [AC_EGREP_CPP([Lucky GNU user],
	[
#include <features.h>
#ifdef __GNU_LIBRARY__
 #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1) || (__GLIBC__ > 2)
  Lucky GNU user
 #endif
#endif
	],
	ac_cv_gnu_library_2_1=yes,
	ac_cv_gnu_library_2_1=no)
      ]
    )
    AC_SUBST(GLIBC21)
    GLIBC21="$ac_cv_gnu_library_2_1"
  ]
)