From f4614658cf06d641e4e5cbb51bd1f7224e5cadc3 Mon Sep 17 00:00:00 2001
From: Abigail <AbigailBuccaneer@users.noreply.github.com>
Date: Mon, 29 May 2017 19:46:11 +0100
Subject: [PATCH] Fix -Wundefined-var-template warning (#963)

This avoids specializing CSingleton<T>::m_instance for each type, and
instead just defines it once in the header. This is allowed by the
standard, multiple definitions are merged in the same way that inline
functions are.
---
 src/app/app.cpp                | 3 ---
 src/app/input.cpp              | 3 ---
 src/app/pathman.cpp            | 2 --
 src/common/config_file.cpp     | 3 ---
 src/common/logger.cpp          | 4 ----
 src/common/settings.cpp        | 2 --
 src/common/singleton.h         | 1 +
 src/graphics/engine/engine.cpp | 2 --
 src/level/robotmain.cpp        | 3 ---
 src/object/object_manager.cpp  | 4 ----
 10 files changed, 1 insertion(+), 26 deletions(-)

diff --git a/src/app/app.cpp b/src/app/app.cpp
index f019ccc0..c780e20e 100644
--- a/src/app/app.cpp
+++ b/src/app/app.cpp
@@ -61,9 +61,6 @@
 #include <getopt.h>
 #include <localename.h>
 
-
-template<> CApplication* CSingleton<CApplication>::m_instance = nullptr;
-
 char CApplication::m_languageLocale[] = { 0 };
 
 
diff --git a/src/app/input.cpp b/src/app/input.cpp
index 87cedf34..142a4554 100644
--- a/src/app/input.cpp
+++ b/src/app/input.cpp
@@ -32,9 +32,6 @@
 #include <boost/lexical_cast.hpp>
 #include <SDL_system.h>
 
-
-template<> CInput* CSingleton<CInput>::m_instance = nullptr;
-
 CInput::CInput()
     : m_keyPresses()
 {
diff --git a/src/app/pathman.cpp b/src/app/pathman.cpp
index a3848280..c5f7e50a 100644
--- a/src/app/pathman.cpp
+++ b/src/app/pathman.cpp
@@ -37,8 +37,6 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/filesystem.hpp>
 
-template<> CPathManager* CSingleton<CPathManager>::m_instance = nullptr;
-
 CPathManager::CPathManager(CSystemUtils* systemUtils)
     : m_systemUtils(systemUtils)
 {
diff --git a/src/common/config_file.cpp b/src/common/config_file.cpp
index 6148eaec..94496ca1 100644
--- a/src/common/config_file.cpp
+++ b/src/common/config_file.cpp
@@ -34,9 +34,6 @@
 #include <boost/property_tree/ini_parser.hpp>
 #include <boost/regex.hpp>
 
-
-template<> CConfigFile* CSingleton<CConfigFile>::m_instance = nullptr;
-
 namespace bp = boost::property_tree;
 
 CConfigFile::CConfigFile()
diff --git a/src/common/logger.cpp b/src/common/logger.cpp
index b5e5b9cb..ed9bdb5d 100644
--- a/src/common/logger.cpp
+++ b/src/common/logger.cpp
@@ -22,10 +22,6 @@
 
 #include <stdio.h>
 
-
-template<> CLogger* CSingleton<CLogger>::m_instance = nullptr;
-
-
 CLogger::CLogger()
 {
     #if DEV_BUILD
diff --git a/src/common/settings.cpp b/src/common/settings.cpp
index 4519b079..8ebd55cc 100644
--- a/src/common/settings.cpp
+++ b/src/common/settings.cpp
@@ -32,8 +32,6 @@
 
 #include "sound/sound.h"
 
-template<> CSettings* CSingleton<CSettings>::m_instance = nullptr;
-
 CSettings::CSettings()
 {
     m_tooltips       = true;
diff --git a/src/common/singleton.h b/src/common/singleton.h
index 005f5243..254fc23d 100644
--- a/src/common/singleton.h
+++ b/src/common/singleton.h
@@ -73,3 +73,4 @@ private:
     CSingleton(const CSingleton<T> &) = delete;
 };
 
+template <typename T> T* CSingleton<T>::m_instance = nullptr;
diff --git a/src/graphics/engine/engine.cpp b/src/graphics/engine/engine.cpp
index 943491b6..0c80c308 100644
--- a/src/graphics/engine/engine.cpp
+++ b/src/graphics/engine/engine.cpp
@@ -64,8 +64,6 @@
 #include <SDL_surface.h>
 #include <SDL_thread.h>
 
-template<> Gfx::CEngine* CSingleton<Gfx::CEngine>::m_instance = nullptr;
-
 // Graphics module namespace
 namespace Gfx
 {
diff --git a/src/level/robotmain.cpp b/src/level/robotmain.cpp
index 6159652e..5f932cbc 100644
--- a/src/level/robotmain.cpp
+++ b/src/level/robotmain.cpp
@@ -125,9 +125,6 @@ const Gfx::Color COLOR_REF_ALIEN = Gfx::Color(135.0f/256.0f, 170.0f/256.0f,  13.
 const Gfx::Color COLOR_REF_GREEN = Gfx::Color(135.0f/256.0f, 170.0f/256.0f,  13.0f/256.0f);  // green
 const Gfx::Color COLOR_REF_WATER = Gfx::Color( 25.0f/256.0f, 255.0f/256.0f, 240.0f/256.0f);  // cyan
 
-
-template<> CRobotMain* CSingleton<CRobotMain>::m_instance = nullptr;
-
 //! Constructor of robot application
 CRobotMain::CRobotMain()
 {
diff --git a/src/object/object_manager.cpp b/src/object/object_manager.cpp
index a33a89fc..e8323a5e 100644
--- a/src/object/object_manager.cpp
+++ b/src/object/object_manager.cpp
@@ -36,10 +36,6 @@
 
 #include <algorithm>
 
-
-template<> CObjectManager* CSingleton<CObjectManager>::m_instance = nullptr;
-
-
 CObjectManager::CObjectManager(Gfx::CEngine* engine,
                                Gfx::CTerrain* terrain,
                                Gfx::COldModelManager* oldModelManager,