For a personal project, a raspberry pi-controlled guitar pedal, i’m creating a small library. This library contains a bunch of classes specifying the the function of several types of effects. For this I have an Effect base-class that every effect inherits from, together with an EffectFactory base-class that will create sequences of effects based on a configuration file. I’m using c++, a language I’m quite new to as I generally use JavaScript.

EffectFactory consists out of a map of strings mapped with pointers to other EffectFactory instances and two functions; one responsible for registering EffectFactory instances to the factories map, and the other a create function that can be overridden by instances of EffectFactory.
My issue arises when I compile the library for testing. I get an error:

undefined reference to `EffectFactory::factories[abi:cxx11]'

There seems to be an issue with using the c++11 ABI. I ran the compiler again with -Wabi-tag added and got:

effect-master/effect.h:22:7: warning: 'EffectFactory' does not have the "cxx11" ABI tag that 'std::string' {aka 'std::__cxx11::basic_string<char>'} (used in the type of 'virtual Effect* EffectFactory::create(std::string)') has [-Wabi-tag]
   22 | class EffectFactory
      |       ^~~~~~~~~~~~~
effect-master/effect.h:26:19: note: 'virtual Effect* EffectFactory::create(std::string)' declared here
   26 |   virtual Effect *create(std::string config);
      |                   ^~~~~~
In file included from f:programsmingwlibgccmingw32.2.0includec++string:55,
                 from f:programsmingwlibgccmingw32.2.0includec++bitslocale_classes.h:40,
                 from f:programsmingwlibgccmingw32.2.0includec++bitsios_base.h:41,
                 from f:programsmingwlibgccmingw32.2.0includec++ios:42,
                 from f:programsmingwlibgccmingw32.2.0includec++ostream:38,
                 from f:programsmingwlibgccmingw32.2.0includec++iostream:39,
                 from effect-master/effect.h:4,
                 from effect-master/effect.cpp:1:
f:programsmingwlibgccmingw32.2.0includec++bitsbasic_string.h:77:11: note: 'std::string' {aka 'std::__cxx11::basic_string<char>'} declared here
   77 |     class basic_string
      |           ^~~~~~~~~~~~
In file included from effect-master/effect.cpp:1:
effect-master/effect.h:29:49: warning: 'EffectFactory::factories' inherits the "cxx11" ABI tag that 'std::map<std::__cxx11::basic_string<char>, EffectFactory*>' (used in its type) has [-Wabi-tag]
   29 |   static std::map<std::string, EffectFactory *> factories;
      |                                                 ^~~~~~~~~
In file included from f:programsmingwlibgccmingw32.2.0includec++map:61,
                 from effect-master/effect.h:6,
                 from effect-master/effect.cpp:1:
f:programsmingwlibgccmingw32.2.0includec++bitsstl_map.h:100:11: note: 'std::map<std::__cxx11::basic_string<char>, EffectFactory*>' declared here
  100 |     class map
      |           ^~~

From what I can gather there seems to be some sort an incompatibility between EffectFactory and both the std::string and the std::map. I spent some time googling and found the solution of using -D_GLIBCXX_USE_CXX11_ABI=0, but this didn’t fix it. I also found this question, but I couldn’t make much sense of it and don’t know if it applies to my situation. Anyone who can help me understand and maybe fix this issue?

For refrence I am using the MinGW g++ compiler.

effect.h

#ifndef EFFECT_H
#define EFFECT_H

#include <iostream>
#include <string>
#include <map>
#include <regex>

class EffectFactory;

class Effect
{
public:
  bool enabled = true;
  void toggleEnabled();
  virtual void triggerAction();
  virtual int eval(int input_signal);

protected:
  int output_signal;
};
class EffectFactory
{
public:
  static void registerType(const std::string &name, EffectFactory *factory);
  virtual Effect *create(std::string config);

private:
  static std::map<std::string, EffectFactory *> factories;
};

#endif

effect.cpp

#include "effect.h"

void Effect::toggleEnabled()
{
  enabled = !enabled;
};
void Effect::triggerAction()
{
  std::cout << "The base triggerAction was triggeredn";
};
int Effect::eval(int input_signal)
{
  std::cout << "The base eval was triggeredn";
  return input_signal;
};

Effect *EffectFactory::create(std::string config)
{
  std::smatch name_match;
  std::regex name_regex("^S+(?:n?)");
  std::regex replace_regex("^S+n?|^ {2}");
  std::regex_search(config, name_match, name_regex);
  config = std::regex_replace(config, replace_regex, "");
  return factories[name_match.str()]->create(config);
};
void EffectFactory::registerType(const std::string &name, EffectFactory *factory)
{
  factories[name] = factory;
};

Source: Windows Questions C++