toupper, toupper_l—translate characters to uppercaseSynopsis
#include <ctype.h> int toupper(int c); int _toupper(int c); #include <ctype.h> int toupper_l(int c, locale_t locale);
Description
toupper is a macro which converts lowercase characters to uppercase,
leaving all other characters unchanged. It is only defined when
c is an integer in the range EOF to 255.
toupper_l is like toupper but performs the function based on the
locale specified by the locale object locale. If locale is
LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined.
You can use a compiled subroutine instead of the macro definition by
undefining this macro using ‘#undef toupper’ or ‘#undef toupper_l’.
_toupper performs the same conversion as toupper, but should
only be used when c is known to be a lowercase character (a–z).
Returns
toupper, toupper_l return the uppercase equivalent of c when
c is a lowercase character, and c otherwise.
_toupper returns the uppercase equivalent of c when it is a
character between a and z. If c is not one of these
characters, the behaviour of _toupper is undefined.
Portability
toupper is ANSI C. _toupper is not recommended for portable programs.
toupper_l is POSIX-1.2008.
No supporting OS subroutines are required.