NAME
isdigit —
decimal-digit character test
LIBRARY
library “libc”
SYNOPSIS
#include
<ctype.h>
int
isdigit(int
c);
DESCRIPTION
Theisdigit()
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.