anonymous namespace

Question

What is the different between these two?

cpp-file:

namespace
{
    int var;
}

or

int var;

if both

Answer 1

In the second case other .cpp files can access the variable as:

extern int var;
var = 42;

and the linker will find it. In the first case the variable name is mangled beyond any reason :) so the above is not possible.