Question

#include <iostream>
#include <stdlib.h>
#include <sstream>

class api
{
private:
    void psParser ()
    {
        std::stringstream psOutput;
        psOutput << "ps --no-headers -f -p " << getpid() << " > .txt";

        system (psOutput.str().c_str());

        std::stringstream processInfo;
        processInfo << ":"__FILE__ << ":" << __DATE__ << ":" << __TIME__ << ":";
    }

public:
    static std::stringstream message;
};

namespace sstreamss
{
    std :: stringstream api :: message;
};

int main ()
{
    api::message << "zxzx";

    return 0;
}

Output:

error: definition of ‘api::message’ is not in namespace enclosing ‘api’

I want that static std::stringstream message should be accessible at a global scope, so I want this under a namespace.

What’s the way out?

Answer 1

I am guessing that you want to have the same instance of api::message accessible across all translation units that have access to api. Unlike plain, non-class static data, which have internal linkage, static class members have external linkage. This means the same instance is seen everywhere. So you do not have to play any games with namespaces. A namespace wouldn’t change anything here, but it would have to enclose the whole api class anyway.