Question

I just stumbled this code:

void somefunction()
{
   throw;
}

and I wonder: what does it mean?

Answer 1

The intent is probably that somefunction() is only ever called from inside some catch block. In that case, there would be an exception active when the throw; is executed, in which case the current exception is re-thrown, to be caught by the next outer handler that can handle that exception type.

If throw; is executed when an exception is not active, it calls terminate() (N4810, §[expr.throw]/4).