Manual Reference Pages  - TOUPPER (3)

NAME

toupper, tolower - convert letter to upper or lower case

CONTENTS

Synopsis
Description
Bugs
Colophon

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 3.44 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/.


GNU TOUPPER (3) 1993-04-04
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