SYNOPSIS
        int extern_call();

DESCRIPTION
        Returns zero, if the function that is currently being executed
        was called by a local call, non-zero for call_other(), driver
        applies, closure calls, etc. Currently the only return value
        for them is 1, but later the various methods may be
        distinguished by means of the return value.

HISTORY
        Introduced in 3.2@263 resp. 3.2.1@12

SEE ALSO
        call_other(E), previous_object(E)