TOUPPER
Section: Linux Programmer's Manual (3)
Updated: April 4, 1993
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.
RETURN VALUE
The value returned is that of the converted letter, or
c
if the conversion was not possible.
CONFORMING TO
ANSI - C, BSD 4.3
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), locale(7)