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toupper, tolower — convert letter to upper or lower case
#include <ctype.h>
int
toupper( |
int c); |
int
tolower( |
int c); |
toupper() converts the
letter c to upper
case, if possible.
tolower() converts the
letter c to lower
case, if possible.
If c is not an
unsigned char value, or
EOF, the behavior of these
functions is undefined.
The value returned is that of the converted letter, or
c if the conversion
was not possible.
The details of what constitutes an uppercase or lowercase letter depend on the current 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.
This page is part of release 3.52 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man−pages/.
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Copyright (c) 1993 by Thomas Koenig (ig25rz.uni-karlsruhe.de) %%%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 under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END Modified Sat Jul 24 17:45:39 1993 by Rik Faith (faithcs.unc.edu) Modified 2000-02-13 by Nicolás Lichtmaier <nickdebian.org> |