windows_dll

A C++ dll creation and dynamic loading usage

1.Creation

Create the class Hello with a simple public function hello() printing 'Hello World'.

In .hpp add

#define HELLO __declspec(dllexport)

That will ease the use of __declspec(dllexport).

Define the hello() function like this:

static void HELLO hello();

Implement the class in the .cpp file.

Build the dll

2.Dump the export

In a Visual Studio command prompt use link /dump /exports your_dll it will display the decorated name of your exported function. It will display string like:

?hello@Hello@@SAXXZ

This is the decorated name of each functions. As you can see you have ?function@Class@something

Create a .def file which will give correspondence between the compiler decorated name and your name:

LIBRARY "your_library"
EXPORTS
    Hello_hello     = ?hello@Hello@@SAXXZ

Then recompile your dll with the def file in the Linker/Input/Module Definition File.

3.Use the dll

First load the lib LoadLibrary("*your_library*") in a HINSTANCE variable.

Find the function with GetProcAddress(HINSTANCE, "function_name") (tip: use auto as a return type)

Call the function with (func)(parameters)

Do not forget to FreeLibrary(HINSTANCE)