netbsd man page for isdigit

ISDIGIT(3)						   BSD Library Functions Manual 						ISDIGIT(3)

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.

BSD
								  April 17, 2008							       BSD