diff --git a/src/BossLife.h b/src/BossLife.h
index 1d5ffc63..28fa00f1 100644
--- a/src/BossLife.h
+++ b/src/BossLife.h
@@ -2,7 +2,15 @@
 
 #include "WindowsWrapper.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void InitBossLife(void);
 BOOL StartBossLife(int code_event);
 BOOL StartBossLife2(void);
 void PutBossLife(void);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/Ending.h b/src/Ending.h
index 54033793..9a749e36 100644
--- a/src/Ending.h
+++ b/src/Ending.h
@@ -4,6 +4,10 @@
 
 #include "CommonDefines.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct CREDIT
 {
 	long size;
@@ -53,3 +57,7 @@ int GetScriptNumber(const char *text);
 void SetCreditIllust(int a);
 void CutCreditIllust(void);
 int Scene_DownIsland(HWND hWnd, int mode);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/Fade.h b/src/Fade.h
index b1f17366..4613be9d 100644
--- a/src/Fade.h
+++ b/src/Fade.h
@@ -2,6 +2,10 @@
 
 #include "WindowsWrapper.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void InitFade(void);
 void SetFadeMask(void);
 void ClearFade(void);
@@ -10,3 +14,7 @@ void StartFadeIn(signed char dir);
 void ProcFade(void);
 void PutFade(void);
 BOOL GetFadeActive(void);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/Flags.h b/src/Flags.h
index 15a6ad2f..97aef8a4 100644
--- a/src/Flags.h
+++ b/src/Flags.h
@@ -2,6 +2,10 @@
 
 #include "WindowsWrapper.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern unsigned char gFlagNPC[1000];
 extern unsigned char gSkipFlag[8];
 
@@ -13,3 +17,7 @@ BOOL GetNPCFlag(long a);
 void SetSkipFlag(long a);
 void CutSkipFlag(long a);
 BOOL GetSkipFlag(long a);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/KeyControl.h b/src/KeyControl.h
index 9063c82b..1a6da5c3 100644
--- a/src/KeyControl.h
+++ b/src/KeyControl.h
@@ -1,5 +1,9 @@
 #pragma once
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 enum KeyBind
 {
 	//The movement keys go in the order of left, right, up and down
@@ -53,3 +57,7 @@ extern long gKeyRight;
 extern long gKeyDown;
 
 void GetTrg(void);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/Main.cpp b/src/Main.cpp
index 757575fb..98450750 100644
--- a/src/Main.cpp
+++ b/src/Main.cpp
@@ -20,6 +20,7 @@
 #include "Organya.h"
 #include "Profile.h"
 #include "Sound.h"
+#include "Tags.h"
 #include "Triangle.h"
 
 LRESULT __stdcall WindowProcedure(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam);
diff --git a/src/Main.h b/src/Main.h
index 09b3e5aa..3acd86b8 100644
--- a/src/Main.h
+++ b/src/Main.h
@@ -2,6 +2,10 @@
 
 #include "WindowsWrapper.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern HWND ghWnd;
 extern BOOL bFullscreen;
 
@@ -9,3 +13,7 @@ void PutFramePerSecound(void);
 unsigned long GetFramePerSecound(void);
 
 BOOL SystemTask(void);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/MiniMap.h b/src/MiniMap.h
index add3aee5..a53fa872 100644
--- a/src/MiniMap.h
+++ b/src/MiniMap.h
@@ -2,9 +2,17 @@
 
 #include "WindowsWrapper.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern char gMapping[0x80];
 
 int MiniMapLoop(void);
 BOOL IsMapping(void);
 void StartMapping(void);
 void SetMapping(int a);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/MycParam.h b/src/MycParam.h
index 5e625bef..d1256d67 100644
--- a/src/MycParam.h
+++ b/src/MycParam.h
@@ -2,16 +2,20 @@
 
 #include "WindowsWrapper.h"
 
-struct ARMS_LEVEL
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct ARMS_LEVEL
 {
 	int exp[3];
-};
+} ARMS_LEVEL;
 
-struct REC
+typedef struct REC
 {
 	long counter[4];
 	unsigned char random[4];
-};
+} REC;
 
 extern ARMS_LEVEL gArmsLevelTable[14];
 
@@ -30,3 +34,7 @@ void PutMyAir(int x, int y);
 void PutTimeCounter(int x, int y);
 BOOL SaveTimeCounter(void);
 int LoadTimeCounter(void);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/PixTone.h b/src/PixTone.h
index 99991309..e8e6c254 100644
--- a/src/PixTone.h
+++ b/src/PixTone.h
@@ -2,15 +2,19 @@
 
 #include "WindowsWrapper.h"
 
-struct PIXTONEPARAMETER2
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct PIXTONEPARAMETER2
 {
 	int model;
 	double num;
 	int top;
 	int offset;
-};
+} PIXTONEPARAMETER2;
 
-struct PIXTONEPARAMETER
+typedef struct PIXTONEPARAMETER
 {
 	int use;
 	int size;
@@ -24,7 +28,11 @@ struct PIXTONEPARAMETER
 	int pointBy;
 	int pointCx;
 	int pointCy;
-};
+} PIXTONEPARAMETER;
 
 void MakeWaveTables(void);
 BOOL MakePixelWaveData(const PIXTONEPARAMETER *ptp, unsigned char *pData);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/Sound.h b/src/Sound.h
index 46a0e032..ef60d65d 100644
--- a/src/Sound.h
+++ b/src/Sound.h
@@ -11,6 +11,10 @@
 
 #include "PixTone.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define SE_MAX 160	// According to the Organya source code release, this is the real name for this constant
 
 enum SoundEffectNames
@@ -42,3 +46,7 @@ void ChangeSoundFrequency(int no, DWORD rate);
 void ChangeSoundVolume(int no, long volume);
 void ChangeSoundPan(int no, long pan);
 int MakePixToneObject(const PIXTONEPARAMETER *ptp, int ptp_num, int no);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/Tags.h b/src/Tags.h
index d66bf478..0bc06aeb 100644
--- a/src/Tags.h
+++ b/src/Tags.h
@@ -2,5 +2,13 @@
 
 #include "WindowsWrapper.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern char gModulePath[MAX_PATH];
 extern char gDataPath[MAX_PATH];
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/TextScr.cpp b/src/TextScr.cpp
index 65119232..a2fa078e 100644
--- a/src/TextScr.cpp
+++ b/src/TextScr.cpp
@@ -120,8 +120,10 @@ void EncryptionBinaryData2(unsigned char *pData, long size)
 // Load generic .tsc
 BOOL LoadTextScript2(const char *name)
 {
-	// Get path
 	char path[MAX_PATH];
+	FILE *fp;
+
+	// Get path
 	sprintf(path, "%s\\%s", gDataPath, name);
 
 	gTS.size = GetFileSizeLong(path);
@@ -129,7 +131,7 @@ BOOL LoadTextScript2(const char *name)
 		return FALSE;
 
 	// Open file
-	FILE *fp = fopen(path, "rb");
+	fp = fopen(path, "rb");
 	if (fp == NULL)
 		return FALSE;
 
@@ -150,15 +152,19 @@ BOOL LoadTextScript2(const char *name)
 // Load stage .tsc
 BOOL LoadTextScript_Stage(const char *name)
 {
-	// Open Head.tsc
 	char path[MAX_PATH];
+	FILE *fp;
+	long head_size;
+	long body_size;
+
+	// Open Head.tsc
 	sprintf(path, "%s\\%s", gDataPath, "Head.tsc");
 
-	long head_size = GetFileSizeLong(path);
+	head_size = GetFileSizeLong(path);
 	if (head_size == INVALID_FILE_SIZE)
 		return FALSE;
 
-	FILE *fp = fopen(path, "rb");
+	fp = fopen(path, "rb");
 	if (fp == NULL)
 		return FALSE;
 
@@ -171,7 +177,7 @@ BOOL LoadTextScript_Stage(const char *name)
 	// Open stage's .tsc
 	sprintf(path, "%s\\%s", gDataPath, name);
 
-	long body_size = GetFileSizeLong(path);
+	body_size = GetFileSizeLong(path);
 	if (body_size == INVALID_FILE_SIZE)
 		return FALSE;
 
diff --git a/src/TextScr.h b/src/TextScr.h
index a073b731..ddfd49ea 100644
--- a/src/TextScr.h
+++ b/src/TextScr.h
@@ -6,7 +6,7 @@
 extern "C" {
 #endif
 
-struct TEXT_SCRIPT
+typedef struct TEXT_SCRIPT
 {
 	// Path (reload when exit teleporter menu/inventory)
 	char path[MAX_PATH];
@@ -55,7 +55,7 @@ struct TEXT_SCRIPT
 
 	// NOD cursor blink
 	unsigned char wait_beam;
-};
+} TEXT_SCRIPT;
 
 BOOL InitTextScript2(void);
 void EndTextScript(void);
diff --git a/vs2003/CSE2.vcproj b/vs2003/CSE2.vcproj
index 033252f3..73cc0ec7 100644
--- a/vs2003/CSE2.vcproj
+++ b/vs2003/CSE2.vcproj
@@ -345,6 +345,12 @@
 			</File>
 			<File
 				RelativePath="..\src\TextScr.cpp">
+				<FileConfiguration
+					Name="Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						CompileAs="1"/>
+				</FileConfiguration>
 			</File>
 			<File
 				RelativePath="..\src\Triangle.cpp">