Convert a long to negative?

This is something really easy but my brain is struggling today. I have a long which has a value of 10. I want to convert it to negative (i.e. -10)

I am using

lValue = lValue - (lValue * 2);

There has to be a simpler bit swapping way of doing it.

Yeah, like:

Code:

lValue = -lValue;

See, I said my brain had given up for the day.