#define _CRT_SECURE_NO_WARNINGS
#include <Windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

BOOL WINAPI DllMain(HINSTANCE hInstDll, DWORD dwReason, LPVOID IpReserved) {
    BOOL bALLWentWell = TRUE;
    switch (dwReason)
    {
    case DLL_PROCESS_ATTACH:
        break;
    case DLL_THREAD_ATTACH:
        break;
    case DLL_THREAD_DETACH:
        break;
    case DLL_PROCESS_DETACH:
        break;
    }
    if (bALLWentWell)
        return TRUE;
    else
    return FALSE;
}

__declspec(dllexport) int Hello(LPWSTR str);

int Hello(LPWSTR str)
{
    MessageBox(NULL, str, L"Проверка связи", MB_OK);
    return 0;
}