[R] keep information on the number of warnings

[Luis Borda de Agua]

I’m using R 3.1.0 in OS X 10.9.4 (Mavericks)

I’m running a function Y that calls a function X which occasionally generates a warning. 
Say that I call the function X 1000 times, and out of these 1000 times I get the following message:

"There were 36 warnings (use warnings() to see them)"

How can I store the number 36 in a variable in function Y?

In other words, how can I extract the information on the number of warnings generated?

Thank you in advance,


Luís Borda de Água