how to activate vim folding markers?

I have inherited some c++ code with vim-based folding markers like this:

// CONSTRUCTORS/DESTRUCTORS /*{{{*/
Foo::Foo()
{
}
Foo::~Foo()
{
}
/*}}}*/

What do I need to put into my .vimrc to enable folding toggles like zm and space-bar?

With my current settings, when I hit space bar inside or zm, vim does nothing.