NAME
    error - test whether a value is an error value

SYNOPSIS
    iserror(x)

TYPES
    x		any

    return	zero or positive integer < 32768

DESCRIPTION
    If x is not an error value, zero is returned.
    If x is an error value, iserror(x) returns its error type.

EXAMPLE
    > a = error(99)
    print iserror(a), iserror(2 + a), iserror(2 + "a"), iserror(2 + 3)
    99 99 3 0

LIMITS
    none

LIBRARY
    none

SEE ALSO
    error, errorcodes