Invalid preprocessor error

[saddique]

I am trying to use "::" in preprocessor directive but am continously getting error for invalid preprocessor directive. can any one tell me replacement of "::"

#include <iostream>
#include <string.h>

#define MACRO(arg) string(::arg)

using namespace std;

int main()
{
   cout<<MACRO(xyz);
   return 0;
}

error: pasting "::" and "xyz" does not give a valid preprocessing token

[Banfa]

It isn't clear what you are trying to achieve using a :: in that location

[weaknessforcats]

Also. there's no xyz to use to expand the macro.

Also, <string.h> is for C. <string> is for C++.