April 17, 2008 TOUPPER 3

### NAME

toupper - lower case to upper case letter conversion

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` toupper(```int c`)

### DESCRIPTION

The toupper(``) function converts a lower-case letter to the corresponding upper-case letter.

### RETURN VALUES

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

### SEE ALSO

ctype(3), isalnum(3), isalpha(3), isascii(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), isxdigit(3), stdio(3), toascii(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 otherwise, the behavior is undefined. See the CAVEATS section of ctype(3) for more details.