[R] There were 50 or more warnings (use warnings() to see the first 50)

[Mag. Ferri Leberl]

I employ R in the Slave-Mode.
The slave returns me the following feedback:

There were 50 or more warnings (use warnings() to see the first 50)

I have found no way so far to get the warnings viewed. Which command would be 
appropriate? warnings() (without an argument) returns NULL.
Thank you in advance.