NAME

toupper, _toupper — lower case to upper case letter conversion

SYNOPSIS

#include <ctype.h>

int
toupper(int c);

int
_toupper(int c);

DESCRIPTION

The toupper() function converts a lower-case letter to the corresponding upper-case letter. The _toupper() function is identical to toupper() except that c must be a lower-case letter.

RETURN VALUES

If the argument to the toupper() function is a lower-case letter, the corresponding upper-case letter is returned if there is one; otherwise the argument is returned unchanged. If the argument to the _toupper() function is a lower-case letter, the corresponding upper-case letter is returned; otherwise the output is undefined.

SEE ALSO

isalnum(3), isalpha(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), isxdigit(3), stdio(3), toascii(3), tolower(3), ascii(7)

STANDARDS

The toupper() function conforms to ANSI X3.159-1989 (“ANSI C89”).

CAVEATS

The argument to toupper must be EOF or representable as an unsigned char; otherwise, the result is undefined.