[R-sig-Geo] How to obtain name of Map object on graphic device?

[Susumu Tanimura]

Hi there,

My question is how to obtain a name of Map object currently on graphic
device.  I had a look at help, documents, or web sites, however, it is
still unclear. 

It is obvious when I myself plot Map object, but I would like to
obtain it automatically inside my function.

Thank you very much in advance.

--
Susumu Tanimura