TOUPPER

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ATTRIBUTES
CONFORMING TO
BUGS
SEE ALSO
COLOPHON

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.

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

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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

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