C++: Warning inconsistent dll linkage
<p>I have an issue with Visual studio (in C++)</p>

<p>I got a warning and I don't know why because I never call 2 time the same variable.</p>

<p><code>function: inconsistent dll linkage</code></p>

<p>warning list: (in french)
<a href="https://i.stack.imgur.com/hapsE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/hapsE.png" alt="warning list - visual studio c++"></a></p>

<p>I read on microsoft: <a href="https://msdn.microsoft.com/query/dev14.query?appId=Dev14IDEF1&amp;l=EN-US&amp;k=k%28C4273%29&amp;rd=true" rel="noreferrer">Compiler Warning (level 1) C4273</a> but I don't really know if it's my problem because the example is not like mine.</p>

<p>I read also <a href="https://stackoverflow.com/questions/2592523/about-inconsistent-dll-linkage">About inconsistent dll linkage (StackOverflow</a> and it tell me that because I use MFC in dll but I didn't check the header MFC.
<a href="https://i.stack.imgur.com/HpGMp.png" rel="noreferrer"><img src="https://i.stack.imgur.com/HpGMp.png" alt="not MFC header"></a></p>

<p>it's my "PayRespectdll.h"</p>

<pre><code>#pragma once

#ifdef PAYRESPECTDLL_EXPORTS
#define PAYRESPECTDLL_API __declspec(dllexport) 
#else
#define PAYRESPECTDLL_API __declspec(dllimport) 
#endif

#include &lt;ctime&gt;
#include &lt;time.h&gt;
#include &lt;string&gt;

namespace PayRespectDLL
{
    class PayRespect
    {
    private:
        static struct std::tm when;
    public:
        static PAYRESPECTDLL_API bool is_setup();
        static PAYRESPECTDLL_API void setup(std::string date);
        static PAYRESPECTDLL_API bool is_possible();
    }
}
</code></pre>

<p>PayRespectDLL.cpp:</p>

<pre><code>// PayRespectDLL.cpp :
//

#include "stdafx.h"
#include "PayRespectDLL.h"
#include &lt;stdexcept&gt;
#include &lt;time.h&gt;
#include &lt;string&gt;
#include &lt;stdlib.h&gt;


using namespace std;

namespace PayRespectdll
{
    bool PayRespect::is_setup()
    {
        return false;//already_setup;
    }

    // setup attempt String: hh:mm:ss.
    void PayRespect::setup(string date)
    {
        return;
    }

    bool PayRespect::is_possible()
    {
        return true;
    }
}
</code></pre>

<p>thank you!</p>