I have some sample code:

interface IFont
{
  IFont createFontWithSize(int size);
}

Main Code:

import common;
class TTFFont : IFont
{
  IFont createFontWithSize(int size){return new TTFFont;}
}

export extern(System) IFont newFont()
{
  auto ret = new TTFFont();
  GC.addRoot(ret);
  return ret;
}

DLL Code:

import common;

Runtime.initialize();
IFont function() newFont;
newFont = loadSymbol("newFont");
IFont myFont = newFont();
IFont otherFont = myFont.createFontWithSize(32); //Gets collected after some time

For it not get collected after some time, I actually need to put GC.addRoot inside the function createFontWithSize. This makes it literally unusable

On Thursday, 27 October 2022 at 02:42:47 UTC, Hipreme wrote:

D DLLs each operate under a separate GC context from the main process, so anything newed in a DLL may be collected if a reference to it isn't maintained there. You can link them together so they share the same GC with something like this:

// mydll.d
extern(C) {
	void gc_setProxy(void* p);
	void gc_clrProxy();
}
export void MyDLL_Initialize(void* gc) {
	gc_setProxy(gc);
}
export void MyDLL_Terminate() {
	gc_clrProxy();
}


// main.d
extern (C) {
	void* gc_getProxy();
}
void main() {
	MyDLL_Initialize(gc_getProxy()); // Share this process's GC with the DLL
	scope(exit) MyDLL_Terminate();
	/* do stuff */
}

Source: http://arsdnet.net/dlang.org/dll.html

On Thursday, 3 November 2022 at 04:38:28 UTC, cc wrote:

Ooooooh this explain so much strange bugs we had with D programs hosting D DLL.

On Thursday, 3 November 2022 at 14:53:19 UTC, Guillaume Piolat wrote:

Are you on the D Discord btw?

On Thursday, 3 November 2022 at 12:33:17 UTC, Adam D Ruppe wrote:

Ah, that's another confusing difference to have to remember. Does the wiki have an up to date list of known compiler differences? Searching for this usually gets me 11-year old stackoverflow threads.