Difficulty using Cxx inside a module

[goretkin]

I had done import Cxx twice in a project, and due to the line

Cxx.jl/src/Cxx.jl

Line 178 in 93359f1

__init__()

this resets the active instances. I personally found this behavior surprising, since all the translation units I had previously loaded were loaded into a different instance.

I thought I could keep a handle to the Cxx.CxxCore.ClangCompiler instance, so I could use it later. It seems that this definition

Cxx.jl/src/clanginstances.jl

Line 40 in 93359f1

instance(C::ClangCompiler) = C

exists for that use.

So I tried
my_cxx_compiler_instance = Cxx.instance(Cxx.__current_compiler__) right after all of my addHeaderDir and cxxinclude calls. And then later
__current_compiler__ = my_cxx_compiler_instance

However the definitions at

Cxx.jl/src/codegen.jl

Lines 840 to 853 in 93359f1

	@generated function cppcall(CT::CxxInstance, expr, args...)
	_cppcall(CT, expr, false, false, args)
	end
	@generated function cppcall_member(CT::CxxInstance, expr, args...)
	_cppcall(CT, expr, true, false, args)
	end
	@generated function cxxnewcall(CT::CxxInstance, expr, args...)
	_cppcall(CT, expr, false, true, args)
	end
	# Memory management
	@generated function destruct(CT::CxxInstance, x)

seem to restrict the type of the first argument to be CxxInstance unnecessarily.

[goretkin]

Actually, I'm not sure exactly what's happening. In the simple MWE below, I see __init__ called exactly once. reset_init! isn't called. In my larger project, I do see these functions called multiple times. In any case, I expect the test below to pass, but it does not.

https://github.com/goretkin/CxxInitMWE/blob/8c56237274d0668bcd1c3051c969387259c2e20f/test/runtests.jl#L7

MWE at https://github.com/goretkin/CxxInitMWE (archive attached for posterity)
CxxInitMWE-master.zip

[goretkin]

My difficulties seem to have been related to precompilation and initialization. Adding __precompile__(false) to my module fixed my issue.

[cdsousa]

Related to #343