[R] check if a certain ... argument has been passed on to my user-defined function

[Mark Heckmann]

Hi,

How can I check if a certain ... argument has been passed on to my
user-defined function or not?

foo <- function(data, ...)
{
### here I want to check whether xlab was passed with the ... arguments
### or if the ... arguments did not contain an xlab argument
}

I tried  missing(xlab)  , exists(xlab) and several other things but did not
find a solution.

TIA,
Mark