NAME
    isatty - returns 1 if fd assocatied with a tty

SYNOPSIS
    isatty(fd)

TYPES
    fd		file

    return	int

DESCRIPTION
    This function returns 1 if fd is associated with a tty, 0 otherwise.


EXAMPLE
    > print isatty(files(0)), isatty(files(1)), isatty(files(2))
	    1 1 1
    > fd = fopen("/dev/null", "r")
    > isatty(fd)
	    0

LIMITS
    fd must be associaed with an open file

LIBRARY
    none

SEE ALSO
    XXX - fill in