NAME
    isatty - returns 1 if fd assocatied with a tty

SYNOPSIS
    isatty(fd)

TYPES
    fd		any

    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
    none

LIBRARY
    none

SEE ALSO
    errno, fclose, feof, ferror, fflush, fgetc, fgetline, fgets, files, fopen,
    fprintf, fputc, fputs, fseek, fsize, ftell, isfile, printf, prompt,
    isassoc, isblk, isconfig, isdefined, iserror, iseven, isfile,
    ishash, isident, isint, islist, ismat, ismult, isnull, isnum, isobj,
    isobjtype, isodd, isprime, isrand, israndom, isreal, isrel,
    issimple, issq, isstr, istype