c++ - .dll Plugin that uses functions defined in the main executable

Question

I have a Main executable that loads .dll/.so Plugins, which works just fine in Linux but on windows(Visual Studio 2012), it fails with undefined reference errors.

The plugin uses functions like session->SendLine("bla") which are defined in the Main executable. (class of session ans methods defined in a .h included in the plugin, but the actual function in a .cpp compiled in main exec).

tl;dr: "I need the windows linker to ignore undefined references in plugins, defined in the main executable"

What is the best way to "make it work" in windows but keep it compatible with Linux without a million #ifdef's?

Answer 1

Linking of libraries on Windows is handled completely differently from how it is handled on Linux. Linking from plugin to host executable is simple on Linux, but not so much on Windows.

On Windows the traditional way to link to an external module is to use an import library, provided by a .lib file. In order to do it that way, you would need to create an import library for your executable file which includes all the exported functions that your plugins need to call. I've never created an import library for an executable. Normally you do it for a DLL. I'm not even sure it will work for an executable.

Some other options:

1. Export the functions from the executable, and use GetProcAddress in your plugin to bind to them at runtime.
2. When you initialize the plugins, pass an interface containing all the functionality that they need.