NAME
isdigit —
decimal-digit character
test
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ctype.h>
int
isdigit(
int
c);
DESCRIPTION
The
isdigit() function tests for any decimal-digit character.
RETURN VALUES
The
isdigit() 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),
isgraph(3),
islower(3),
isprint(3),
ispunct(3),
isspace(3),
isupper(3),
isxdigit(3),
stdio(3),
toascii(3),
tolower(3),
toupper(3),
ascii(7)
STANDARDS
The
isdigit() function conforms to
ANSI
X3.159-1989 (“ANSI C89”).
CAVEATS
The argument to
isdigit() must be
EOF
or representable as an
unsigned char; otherwise, the
behavior is undefined. See the
CAVEATS
section of
ctype(3) for more
details.