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ISUPPER(3) |
Library Functions Manual |
ISUPPER(3) |
NAME
isupper — upper-case character test
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ctype.h>
int
isupper(int c);
DESCRIPTION
The
isupper() function tests for any upper-case letter or any of an implementation-defined set of characters for which none of
iscntrl(3),
isdigit(3),
ispunct(3), or
isspace(3) is true. In the
``C'' locale,
isupper() returns true only for the characters defined as upper-case letters.
RETURN VALUES
The isupper() function returns zero if the character tests false and returns non-zero if the character tests true.
SEE ALSO
ctype(3),
isalnum(3),
isalpha(3),
isascii(3),
isblank(3),
iscntrl(3),
isdigit(3),
isgraph(3),
islower(3),
isprint(3),
ispunct(3),
isspace(3),
isxdigit(3),
stdio(3),
toascii(3),
tolower(3),
toupper(3),
ascii(7)
STANDARDS
The isupper() function conforms to ANSI X3.159-1989 (“ANSI C89”).
CAVEATS
The argument to
isupper() must be
EOF or representable as an
unsigned char; otherwise, the behavior is undefined. See the
CAVEATS section of
ctype(3) for more details.