Scope of the c++ using directive
- by ThomasMcLeod
From section 7.3.4.2 of the c++11 standard:
A using-directive specifies that the names in the nominated namespace
can be used in the scope in which the using-directive appears after
the using-directive. During unqualified name lookup (3.4.1), the names
appear as if they were declared in the nearest enclosing namespace
which contains both the using-directive and the nominated namespace. [
Note: In this context, “contains” means “contains directly or
indirectly”. —end note ]
What do the second and third sentences mean exactly? Please give example.
Here is the code I am attempting to understand:
namespace A
{
int i = 7;
}
namespace B
{
using namespace A;
int i = i + 11;
}
int main(int argc, char * argv[])
{
std::cout << A::i << " " << B::i << std::endl;
return 0;
}
It print "7 7" and not "7 18" as I would expect.
Sorry for the typo, the program actually prints "7 11".
