TOUPPER
Section: Linux Programmer's Manual (3)
Updated: 1993-04-04
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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.
CONFORMING TO
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 3.27 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- CONFORMING TO
-
- BUGS
-
- SEE ALSO
-
- COLOPHON
-
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