Question

If I have a #define statement within a namespace as such:

namespace MyNamespace
{
  #define SOME_VALUE 0xDEADBABE
}

Am I correct in saying that the #define statement is not restricted to the namespace?

Is the following the “correct” thing to do?

namespace MyNamespace
{
  const unsigned int SOME_VALUE = 0xDEADBABE;
}

Answer 1

Correct,#define‘s aren’t bound by namespaces. #define is a preprocessor directive – it results in manipulation of the source file prior to being compiled via the compiler. Namespaces are used during the compilation step and the compiler has no insight into the #define‘s.

You should try to avoid the preprocessor as much as possible. For constant values like this, prefer const over #define‘s.