NAME
toupper —
lower case to upper case
letter conversion
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ctype.h>
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
unsigned char; otherwise, the
behavior is undefined. See the
CAVEATS
section of
ctype(3) for more
details.