The namespace starts with :: in C++ [duplicate]

Question

Possible Duplicate:
What's the purpose of a leading “::” in a C++ method call

This gtest has the example code.

::testing::AssertionResult IsEven(int n) {
  if ((n % 2) == 0)
    return ::testing::AssertionSuccess();
  else
    return ::testing::AssertionFailure() << n << " is odd";
}

How does it work? If the namespace is testing, isn't it testing::AssertionResult is the right usage?

Answer 1

The :: prefix refers to the global namespace, so this is like an absolute versus relative path specification.