[oolua] Issue #9: when Selectively Exporting C Functions to lua in Member functions of two classes in the same namespace, the compiler report a linking error (liamdevine/oolua)

From: "Oscar Zhao" <issues-reply@xxxxxxxxxxxxx>
To: oolua@xxxxxxxxxxxxx
Date: Tue, 30 Sep 2014 10:17:05 -0000
New issue 9: when Selectively Exporting C Functions to lua in Member functions 
of two classes in the same namespace, the compiler report a linking error
https://bitbucket.org/liamdevine/oolua/issue/9/when-selectively-exporting-c-functions-to

Oscar Zhao:

The circumstance is such: There are several C++ functions to export to lua and 
two classes ( LuaWrapper, YourLuaWrapper).  In the member functions of 
LuaWrapper( and YourLuaWrapper), I want to export the C++ functions defined 
before.  Then I put the OOLUA_CFUNC(...) in a single header file, and let the 
LuaWrapper.cpp and YourLuaWrapper.cpp include the header file.  There are 
corresponding "OOLUA::set_global(..)" in the definition of member functions.  
<br />Before this, I always put OOLUA_CFUNC and OOLUA::set_global in the same 
cpp file, and no problems found.  The error is the following:

```
#!lua

1>------ Build started: Project: ExportCFuncInFunctions, Configuration: Debug 
Win32 ------
1>Compiling...
1>LuaWrapper.cpp
1>YourLuaWrapper.cpp
1>Generating Code...
1>Linking...
1>YourLuaWrapper.obj : error LNK2005: "bool __cdecl ttservice::isBool(void)" 
(?isBool@ttservice@@YA_NXZ) already defined in LuaWrapper.obj
1>YourLuaWrapper.obj : error LNK2005: "bool __cdecl ttservice::isInt(void)" 
(?isInt@ttservice@@YA_NXZ) already defined in LuaWrapper.obj
1>YourLuaWrapper.obj : error LNK2005: "bool __cdecl ttservice::isDouble(void)" 
(?isDouble@ttservice@@YA_NXZ) already defined in LuaWrapper.obj
1>YourLuaWrapper.obj : error LNK2005: "bool __cdecl ttservice::isString(void)" 
(?isString@ttservice@@YA_NXZ) already defined in LuaWrapper.obj
1>YourLuaWrapper.obj : error LNK2005: "int __cdecl 
ttservice::oolua_isBool(struct lua_State *)" 
(?oolua_isBool@ttservice@@YAHPAUlua_State@@@Z) already defined in LuaWrapper.obj
1>YourLuaWrapper.obj : error LNK2005: "int __cdecl 
ttservice::oolua_isInt(struct lua_State *)" 
(?oolua_isInt@ttservice@@YAHPAUlua_State@@@Z) already defined in LuaWrapper.obj
1>YourLuaWrapper.obj : error LNK2005: "int __cdecl 
ttservice::oolua_isDouble(struct lua_State *)" 
(?oolua_isDouble@ttservice@@YAHPAUlua_State@@@Z) already defined in 
LuaWrapper.obj
1>YourLuaWrapper.obj : error LNK2005: "int __cdecl 
ttservice::oolua_isString(struct lua_State *)" 
(?oolua_isString@ttservice@@YAHPAUlua_State@@@Z) already defined in 
LuaWrapper.obj
1>E:\work\Git\OOLua\OOLuaTest\_runtime\Debug\\ExportCFuncInFunctions.exe : 
fatal error LNK1169: one or more multiply defined symbols found
1>Build log was saved at 
"file://E:\work\Git\OOLua\OOLuaTest\_builder\Debug\ExportCFuncInFunctions\BuildLog.htm"
1>ExportCFuncInFunctions - 9 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
```

**SOURCE Code:**
FunctionsToExport.h

```
#!c++

#ifndef FUNCTIONS_TO_EXPORT_H__
#define FUNCTIONS_TO_EXPORT_H__

#include "oolua.h"

namespace ttservice
{
    bool isBool(){ return true; }
    bool isInt(){ return true; }
    bool isDouble(){ return true; }
    bool isString(){ return true; }
}
#endif
```

FunctionsRegist.h

```
#!c++

#ifndef FUNCTION_REGIST_H_
#define FUNCTION_REGIST_H_

#include "oolua.h"
#include "FunctionsToExport.h"

namespace ttservice
{
    OOLUA_CFUNC(isBool, oolua_isBool)
    OOLUA_CFUNC(isInt, oolua_isInt)
    OOLUA_CFUNC(isDouble, oolua_isDouble)
    OOLUA_CFUNC(isString, oolua_isString)
}   
#endif
```

LuaWrapper.h

```
#!c++

#ifndef LUA_WRAPPER_H_
#define LUA_WRAPPER_H_

#include "oolua.h"

namespace ttservice
{
    class LuaWrapper
    {
    public:
        LuaWrapper(): vm(new OOLUA::Script){}
        ~LuaWrapper();

        void regist_one_function();
        void regist_all_functions();

    private:
        OOLUA::Script* vm;
    };
}
#endif
```

LuaWrapper.cpp

```
#!c++

#include "LuaWrapper.h"
#include "oolua.h"
#include "FunctionsRegist.h"

namespace ttservice
{
    LuaWrapper::~LuaWrapper()
    {
        if(vm) delete vm; 
    }

    void LuaWrapper::regist_one_function()
    {
        OOLUA::set_global(*vm, "isBool", oolua_isBool);
    }

    void LuaWrapper::regist_all_functions()
    {
        OOLUA::set_global(*vm, "isBool", oolua_isBool);
        OOLUA::set_global(*vm, "isInt", oolua_isInt);
        OOLUA::set_global(*vm, "isDouble", oolua_isDouble);
        OOLUA::set_global(*vm, "isString", oolua_isString);
    }
}
```

YourLuaWrapper.h

```
#!c++

#ifndef YOUR_LUA_WRAPPER_H_
#define YOUR_LUA_WRAPPER_H_

#include "oolua.h"

namespace ttservice
{
    class YourLuaWrapper
    {
        YourLuaWrapper():vm(new OOLUA::Script){}
        ~YourLuaWrapper();
        void regist_one_function();
        void regist_all_functions();

    private:
        OOLUA::Script* vm;
    };
}   
#endif
```

YourLuaWrapper.cpp

```
#!c++

#include "YourLuaWrapper.h"
#include "oolua.h"
#include "FunctionsRegist.h"

namespace ttservice
{
    YourLuaWrapper::~YourLuaWrapper()
    {
        if(vm) delete vm; 
    }

    void YourLuaWrapper::regist_one_function()
    {
        OOLUA::set_global(*vm, "isBool", oolua_isBool);
    }

    void YourLuaWrapper::regist_all_functions()
    {
        OOLUA::set_global(*vm, "isBool", oolua_isBool);
        OOLUA::set_global(*vm, "isInt", oolua_isInt);
        OOLUA::set_global(*vm, "isDouble", oolua_isDouble);
        OOLUA::set_global(*vm, "isString", oolua_isString);
    }
}
```
[oolua] Issue #9: when Selectively Exporting C Functions to lua in Member functions of two classes in the same namespace, the compiler report a linking error (liamdevine/oolua)

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