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`stdstd::string` string is a useful tool for simplifying memory management of strings and avoiding unnecessary copies by reference counting. However there is one common gotcha where it ''causes'' unnecessary copies. Consider:

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This actually allocates, copies and deletes 1000 heap buffers with the string "hello"! The problem here is that "hello" is ''not'' an instance of `stdstd::string`string. It is a `charchar[5` ] that must be converted to a temporary `stdstd::string` string using the appropriate constructor. However `stdstd::string` string always wants to manage its own memory, so the constructor allocates a new buffer and copies the string. Once f() returns and we go round the loop again the temporary is deleted along with its buffer.

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This time we have a constant `stdstd::string` string that is created once at start up and destroyed once at shut-down. The anonymous namespace makes the constant private to this ` .cpp` cpp file so we wont have name clashes. (Its similar to using the `static` static keyword on a global declaration in C, but anonymous namespaces are the preferred way to do it in modern C++)