isupper
—
upper-case character test
Standard C Library (libc, -lc)
#include <ctype.h>
int
isupper
(int
c);
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.
The isupper
() function returns zero if the character
tests false and returns non-zero if the character tests true.
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)
The isupper
() function conforms to ANSI
X3.159-1989 (“ANSI C89”).
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.