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)