Компиляция и использование DLL

#include <windows.h>
#include <iostream>
int (*TestAddValFuncFromExtDLL)(int, int);
int main() {
    HINSTANCE hinstLib = LoadLibrary("TestDLL.dll");
    TestAddValFuncFromExtDLL = (int(*)(int, int)) GetProcAddress(hinstLib, "TestAddValFuncFromExtDLL");
    TestAddValFuncFromExtDLL(10, 15);
}

#include <windows.h>
#include <iostream>
int *TestAddValFuncFromExtDLL(int, int);
int main() {
    HINSTANCE hinstLib = LoadLibrary("TestDLL.dll");
    TestAddValFuncFromExtDLL = (int*(int, int)) GetProcAddress(hinstLib, "TestAddValFuncFromExtDLL");
    TestAddValFuncFromExtDLL(10, 15);
}

#include <iostream>
#include <type_traits>
 
int funct1(int, int) {return 1;}
int *funct2(int, int) {return nullptr;}
 
int main()
{
    std::cout << std::boolalpha;      
    std::cout << "types_equal " << std::is_same< decltype(&funct1), int (*)(int, int) >::value << std::endl;    //указатель на функцию
    std::cout << "types_equal " << std::is_same< decltype(funct2), int *(int, int) >::value << std::endl;       //просто функция  
}

(*TestAddValFuncFromExtDLL)(10, 15);

HINSTANCE hinstLib = LoadLibrary("TestDLL.dll");

#define LoadLibrary __AW_SUFFIXED__(LoadLibrary)
WINBASEAPI HINSTANCE WINAPI LoadLibraryA (LPCSTR);
WINBASEAPI HINSTANCE WINAPI LoadLibraryW (LPCWSTR);

/* Related to the UNICODE macro definition, there are many functions in
 * the Win32 API with a generic name, which is mapped to a variant with
 * wchar_t UTF-16LE encoding of string arguments, in cases when UNICODE
 * is defined, as facilitated by the following macro...
 */
#ifdef UNICODE
 /* ...by appending a "W" suffix to the generic function name...
  */
# define __AW_SUFFIXED__(__NAME__)  __NAME__##W
#else
 /* ...or by appending an "A" suffix, to select an ANSI variant with
  * char encoding of string arguments, when UNICODE is not defined.
  */
# define __AW_SUFFIXED__(__NAME__)  __NAME__##A
#endif