toupper, tolower: převést písmeno na velká nebo malá písmena

Originální popis anglicky: toupper, tolower - convert letter to upper or lower case

Návod, kniha: Linux Programmer's Manual

STRUČNĚ

#include <ctype.h>
 
int toupper(int c);
int tolower(int c);

POPIS / INSTRUKCE

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 behaviour of these functions is undefined.

NÁVRATOVÁ HODNOTA

The value returned is that of the converted letter, or c if the conversion was not possible.

ODPOVÍDAJÍCÍ

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.

SOUVISEJÍCÍ

isalpha(3), setlocale(3), locale(7)