NAME¶
toupper, tolower - convert letter to upper or lower case
SYNOPSIS¶
#include <ctype.h>
int toupper(int c);
int tolower(int c);
DESCRIPTION¶
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.
RETURN VALUE¶
The value returned is that of the converted letter, or
c if the
conversion was not possible.
C89, C99, 4.3BSD.
BUGS¶
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.
SEE ALSO¶
isalpha(3),
setlocale(3),
towlower(3),
towupper(3),
locale(7)
COLOPHON¶
This page is part of release 3.44 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/.
