tolower_l (3)
Leading comments
Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de) and Copyright 2014 Michael Kerrisk <mtk.manpages@gmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed...
NAME
toupper, tolower, toupper_l, tolower_l - convert uppercase or lowercaseSYNOPSIS
#include <ctype.h> int toupper(int c);
int tolower(int c); int toupper_l(int c, locale_t locale); int tolower_l(int c, locale_t locale);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
toupper_l(), tolower_l():
-
- Since glibc 2.10:
- _XOPEN_SOURCE >= 700
- Before glibc 2.10:
- _GNU_SOURCE
DESCRIPTION
These functions convert lowercase letters to uppercase, and vice versa.If c is a lowercase letter, toupper() returns its uppercase equivalent, if an uppercase representation exists in the current locale. Otherwise, it returns c. The toupper_l() function performs the same task, but uses the locale referred to by the locale handle locale.
If c is a uppercase letter, tolower() returns its lowercase equivalent, if a lowercase representation exists in the current locale. Otherwise, it returns c. The tolower_l() function performs the same task, but uses the locale referred to by the locale handle locale.
If
c
is neither an
unsigned char
value nor
EOF,
the behavior of these functions
is undefined.
The behavior of
toupper_l()
and
tolower_l()
is undefined if
locale
is the special locale object
LC_GLOBAL_LOCALE
(see
duplocale(3))
or is not a valid locale object handle.
RETURN VALUE
The value returned is that of the converted letter, or c if the conversion was not possible.ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).| Interface | Attribute | Value |
|
toupper(),
tolower(),
toupper_l(), tolower_l() | Thread safety | MT-Safe |
CONFORMING TO
toupper(), tolower(): C89, C99, 4.3BSD, POSIX.1-2001, POSIX.1-2008.toupper_l(), tolower_l(): POSIX.1-2008.
NOTES
The details of what constitutes an uppercase or lowercase letter depend on the locale. For example, the default C locale does not know about umlauts, so no conversion is done for them.In some non-English locales, there are lowercase letters with no corresponding uppercase equivalent; the German sharp s is one example.