NAME
    isblk - whether or not a value is a block

SYNOPSIS
    isblk(val)

TYPES
    val		any

    return	0, 1, or 2

DESCRIPTION
    isblk(val) returns 1 if val is an unnamed block, 2 if val is a
    named block, 0 otherwise.

    Note that a named block B retains its name after its data block is
    freed by rmblk(B).  That a named block B has null data block may be
    tested using sizeof(B);  this returns 0 if and only if the memory
    has been freed.

EXAMPLE
    > A = blk()
    > isblk(A)
	1

    > B = blk("beta")
    > isblk(B)
	2

    > isblk(3)
	0

LIMITS
    none

LIBRARY
    none - XXX ???

SEE ALSO
    blk, blocks, blkfree,
    isassoc, isatty, 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