So that does indeed solve some of the problems.  However, using this method, when linking I get two errors, undefined reference rt_init() and rt_term() I had just put these methods in the header file.  If I put wrappers around these functions and export I get the rt_init, rt_term is private.

On Tuesday, 5 August 2014 at 21:28:08 UTC, David Soria Parra wrote:
> On Monday, 4 August 2014 at 20:48:09 UTC, Jon wrote:
>
>> For reasons I don't completely understand, you also need a fake main function, dummy.d:
>>
>>    void main(){}
>>
>
> Note that this is not necessary if you compile with -lib e.g.:
>
>   dmd -lib -oflibtest.a test.d
>
> and then
>
>   ghc Main.hs --make -omain libtest.a
>
> I don't have gdc or ldc installed but as far as I know ldc has a -lib flag as well.

On Tuesday, 5 August 2014 at 23:23:43 UTC, Jon wrote:
> So that does indeed solve some of the problems.  However, using this method, when linking I get two errors, undefined reference rt_init() and rt_term() I had just put these methods in the header file.  If I put wrappers around these functions and export I get the rt_init, rt_term is private.
>

It works for me, here are the main parts of my Makefile:

DC = ~/bin/dmd

main: Main.hs FunctionsInD.a
	ghc -o main Main.hs FunctionsInD.a ~/lib/libphobos2.a -lpthread

FunctionsInD.a: FunctionsInD.d
	$(DC) -c -lib FunctionsInD.d

I passed in the phobos object directly because I don't know how to specify the "~/lib" directory on the ghc command line.

Jon via Digitalmars-d-learn <digitalmars-d-learn@puremagic.com> writes:

> So that does indeed solve some of the problems.  However, using this method, when linking I get two errors, undefined reference rt_init() and rt_term() I had just put these methods in the header file.  If I put wrappers around these functions and export I get the rt_init, rt_term is private.
>

rt_init is part of druntime. You need to link druntime into your program in order to make it work.

Hi, thank you!! I have modified the program based on a previous suggestion.  rt_init is called before using any D functionality and rt_term is called after using D functionality.  I did this by:
  1) Placing int rt_init(); and int rt_term(); into the header file that Haskell reads
  2) Creating Haskell stubs
   foreign import ccall unsafe "FunctionsInD.h rt_init"
       d_init :: IO CInt
   foreign import ccall unsafe "FunctionsInD.h rt_term"
       d_term :: IO CInt
And then in the Main haskell program, in main, the function starts with
    d_init
and ends with
    d_term
I'm pretty sure this is working nicely, because I can allocate structs with the "new" keyword in D, and this led to segfaults before using rt_init and rt_term.

I think the problem I was having was trying to do this in a stupid way i.e. put wrappers around init and term on the D side.

However, I still do not know how to compile without the using a fake main.  Compiling with -c -lib does still give me a _Dmain undefined reference.  I did
    dmd -c -lib FunctionsInD.d
    ghc --make Main.hs FunctionsInD.a -lphobos2
And get
    /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu/libphobos2.so: undefined reference to `_Dmain'

On Wednesday, 6 August 2014 at 11:03:33 UTC, David Soria Parra via Digitalmars-d-learn wrote:
> Jon via Digitalmars-d-learn <digitalmars-d-learn@puremagic.com> writes:
>
>> So that does indeed solve some of the problems.  However, using this
>> method, when linking I get two errors, undefined reference rt_init()
>> and rt_term() I had just put these methods in the header file.
>>  If I
>> put wrappers around these functions and export I get the rt_init,
>> rt_term is private.
>>
>
> rt_init is part of druntime. You need to link druntime into your program
> in order to make it work.