Feature Request: A mechanism for unloading and reloading unmanaged libraries while using P/Invoke

[hez2010]

Currently there's no way to unload unmanaged dynamic libraries while using P/Invoke.

Sometimes we need to hot-upgrade without restarting host process, absolutely that we can use LoadLibrary/FreeLibrary to achieve that but it's really inconvenient, and also we cannot invoke methods in dll directly by calling their method names/ordinals.

So I think it is necessary to provide a mechanism for unloading/reloading dlls while using P/Invoke.

[RussKeldorph]

@janvorli

[AaronRobinsonMSFT]

This isn't something we are likely to change via the DllImport approach. There are several reasons, but mostly it will lead to invalid P/Invoke stubs that could result in unsafe execution if the associated native library is unloaded.

absolutely that we can use LoadLibrary/FreeLibrary to achieve that but it's really inconvenient, and also we cannot invoke methods in dll directly by calling their method names/ordinals.

Agreed. The proposed C# function pointer feature along with the NativeLibrary should make much of this less onerous.

[tapika]

Agreed. The proposed C# function pointer feature along with the NativeLibrary should make much
of this less onerous.

I guess this is one more dynamic approach how to proceed. But would it be possible to introduce some additional function call to release loaded library, which was used with [DllImport] attribute.

Then [DllImport] can be used as such, without need to coding everything dynamically via NativeLibrary.

Btw, one approach is to create customized [DllImport], which would in a turn use NativeLibrary, and provide function for release loaded dll. (Reinvent the wheel)