Emulating DLL

[Craig]

On Monday, 18 March 2019 at 22:59:12 UTC, Ethan Watson wrote:
> On Monday, 18 March 2019 at 22:50:57 UTC, Craig wrote:
>> Is it possible to create a D module that has functions in it, 
>> and then use those functions dynamically at run time emulating 
>> DLL like functionality?
>
> On Monday, 18 March 2019 at 22:50:57 UTC, Craig wrote:
>> Is it possible to create a D module that has functions in it, 
>> and then use those functions dynamically at run time emulating 
>> DLL like functionality?
>
> I've talked extensively on this topic at DConf over the last 
> few years.
>
> http://dconf.org/2016/talks/watson.html
> http://dconf.org/2017/talks/watson.html
> http://dconf.org/2018/talks/watson.html
>
> https://github.com/GooberMan/binderoo
>
> It's not a simple thing by any means, there's plenty of little 
> implementation details that you'll need to be aware of. But 
> yes, it's quite possible.

This seems overly complex for what I want and not exactly what I 
need. I'm looking for simply that simply lets me call functions 
that exist in an external dynamically accessible file.

In my host code I will use a function like "foo" but that foo 
will be a function pointer that can point to the external code. I 
don't need a bunch of bells and whistles or complex ways to 
accomplish this.

1. Load up external code,
2. Fixup whatever needs fixing up to make the code work properly
3. Point function pointer to code.
4. Call.

For simple functions such as pure functions step 2 can be skipped 
and hence it is essentially just loading the code in to memory 
and calling it.

I do get that in general it is more complex but other than 
relocatable code, initialization, and the GC, it shouldn't 
require much more work.


For example, with windows I could simply compile to a dll then 
extract the code, or just use LoadLibrary and it effectively does 
all the work(steps 1 & 2 & 3).

LoadLibrary is not portable though and seems excessive to do 
something that should be rather simple unless there is something 
I'm missing that has to be done that is complex. Relocation is 
easy if one has the appropriate locations to fix up which are 
generally included in the binary somewhere. The GC and rt can be 
initialized easily.