view doc/c-strcasestr.texi @ 17321:896204e6fbfc

extensions: port better to MINUX 3, HP-UX, autoheader 2.62 Some of these changes are merged in from git Autoconf. * m4/extensions.m4 (AC_USE_SYSTEM_EXTENSIONS): When deciding whether to define _XOPEN_SOURCE, inspect the preprocessor macro __hpux instead of the more-heavyweight operation of requiring AC_CANONICAL_HOST. Define _NETBSD_HOST on MINUX, for MINUX 3. Use USE_SYSTEM_EXTENSIONS, not __EXTENSIONS__, as the key for __EXTENSIONS__.
author Paul Eggert <>
date Wed, 06 Feb 2013 22:41:08 -0800
parents e542fd46ad6f
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@c Documentation of gnulib module 'c-strcasestr'.

@c Copyright (C) 2008-2013 Free Software Foundation, Inc.

@c Permission is granted to copy, distribute and/or modify this document
@c under the terms of the GNU Free Documentation License, Version 1.3 or
@c any later version published by the Free Software Foundation; with no
@c Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
@c Texts.  A copy of the license is included in the ``GNU Free
@c Documentation License'' file as part of this distribution.

The @code{c-strcasestr} module contains a case-insensitive string search
function operating on single-byte character strings, that operate as if the
locale encoding was ASCII.
(The "C" locale on many systems has the locale encoding "ASCII".)

The function is:
extern char *c_strcasestr (const char *haystack, const char *needle);
@end smallexample

For case conversion here, only ASCII characters are considered to be
upper case or lower case.

Note: The function @code{strcasestr} from @code{<string.h>} supports only
unibyte locales; for multibyte locales, you need the function