static variable resolution at build time

Question

I have files that are linked together:

basic.h

#pragma once

extern const string APPLICATION_NAME;

application.cpp

#include "basic.h"

const string APPLICATION_NAME = "MyApplication";

............

---

ErrorTables.h

class ErrorTable
{
public:
    ErrorTable();

private:
    map <index, errorRecord> _errorTable;


};

---

ErrorTables.cpp

#include "basic.h"

ErrorTable TheErrorTable;

ErrorTable::ErrorTable()
{
   ...
   _errorTable[errorIndex] = errorRecord(APPLICATION_NAME + " hit some error.");
   ...
}

---

This code can be built and run OK in Visual Studio. When I use GCC, it can be build but failed in run time. The problem is in TheErrorTable that has static linkage and is created before main() is started; it can't resolve APPLICATION_NAME variable. If I hide it using local variable everything works OK.

Is there a GCC flag that force resolution of a static variable during build time or implements behavior of Visual Studio in some other way?

Answer 1

The problem is in TheErrorTable that has static linkage and is created before main() is started; it can't resolve APPLICATION_NAME variable.

That's right. Either TheErrorTable or APPLICATION_NAME is initialised first, and you can't fix this.

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Make ErrorTable not be a global. You cannot define the order of static initialisation across TUs, and even if you could you'd just be making the code harder to follow.

I hate to say it, but ErrorTable might benefit from the singleton pattern here (because function-statics have sane initialisation order), at least in as much as that it's the solution closest to your existing code.

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Update

As @godexsoft alluded to, you can get around this by taking advantage of constant initialisation and making APPLICATION_NAME a char const* rather than a std::string; your initialiser will then be a constant-expression initialiser without a constructor call, and as such will be invoked — across TUs — before any ErrorTable, guaranteed. (Really? Yes.)