BlitzMax types and dlls

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Leadwerks

I have found that it passing BlitzMax types to and from a BlitzMax dll works perfectly, even with other languages. I would recommend declaring the variables as a byte ptr in the main program, and having the BlitzMax dll return the type.

DLL function:

Function SubmeshSurface_:TSurface(hsubmesh:Int) "win32"
	GCEnter()
	Local submesh:TSubmesh
	submesh=TSubmesh(HandleToObject(hsubmesh))
	Return submesh.surface
EndFunction

Function CountVertices_:Int(surface:TSurface) "win32"
	GCEnter()
	Return surface.CountVertices()
EndFunction

Main program:

Global SubmeshSurface:Byte Ptr(hsubmesh:Int) "win32"
Global CountVertices:Int(surface:Byte Ptr) "win32"

Obviously it is your responsibility to manage the memory, but for types that always get stored in a list and have a Free() command, this approach will work just fine.

The only problem I have found is that the BlitzMax dll does not seem to recognize Null when it is passed. When I pass Null to this DLL function from the main program, the dll always thinks that a valid object was passed:

Function LoadMesh_:Int(cs:Byte Ptr,oparent:TEntity) "win32"
	GCEnter()
	Local parent:TEntity
	Local mesh:TMesh
	Local path$
	If oparent=Null Notify "null parent" Else Notify "Something was passed, muthafucka!"
	parent=TEntity(oparent)
	'parent=TEntity(HandleToObject(hparent))
	path=String.fromcstring(cs)
	mesh=LoadMesh(path,parent)
	If mesh Return mesh.handle
EndFunction