Usage of GetProcAddress confused non executing - c++

Question

I might be missing something very easy but still i confronted this problem that i couldnt solve. I create a dll with these functions,
extern "C"{
__declspec(dllexport) void some();
__declspec(dllexport) void printer();
}
void printer()
{
printf("printing...\n");
}
i compile it using cmake
cmake .. -G "Visual Studio 15 2017" -A x64 -DBUILD_SHARED_LIBS=TRUE
cmake --build . --config Release
the i load it from my dllloader.cpp
int main() {
HINSTANCE hGetProcIDDLL = LoadLibrary("mydll.dll");
if (hGetProcIDDLL == NULL) {
std::cout << "cannot locate the .dll file" << std::endl;
} else {
std::cout << "it has been called" << std::endl;
}
if(GetProcAddress(hGetProcIDDLL, "printer") == NULL){
}else{
std::cout <<"not null" << std::endl;
}
std::cout << GetLastError() << " err" << std::endl;
getchar();
return 0;
}
So GetLastError returns 0 but nothing is printed, in the original file it is pretty much the same, the function is more that just a printf() call but the function gets loaded, how do we run it ? I know i might be missing something, just function does not execute. Any help is appreciated

Answer 1

typedef void(*my_dll_print)(); // function pointer to print method of dll
int main()
{
HINSTANCE hGetProcIDDLL = LoadLibrary("mydll.dll");
if (hGetProcIDDLL == nullptr)
std::cout << "cannot locate the .dll file" << std::endl;
else
std::cout << "it has been called" << std::endl;
my_dll_print print_method = reinterpret_cast<my_dll_print>(GetProcAddress(hGetProcIDDLL, "printer")); // Extract method address and create pointer
if (print_method == nullptr)
std::cout << "is null" << std::endl;
else
print_method(); // Call dll method
std::cout << GetLastError() << " err" << std::endl;
getchar();
return 0;
}
Try to use nullptr instead NULL to check pointer.
GetProcAdrress retrieves the address of an exported function or variable from the specified dynamic-link library! and makes no function call. You must first assign to function pointer then make call to pointed function!