Hi,
Is it possible to write shared objects for linux with DMD? If "yes", how
would one do that - and if "no", when will DMD be able to compile to
shared objects?

BG
Nicolai Waniek

> Is it possible to write shared objects for linux with DMD?

Yes. I've only tried it with a single file, but it should work. Use dmd -c to compile without linking and then link manually with gcc <object-files> -shared <your flags> -o lib<name>.so.

I hope that helps,
Christian

Christian Kamm wrote:
>> Is it possible to write shared objects for linux with DMD?
> 
> Yes. I've only tried it with a single file, but it should work. Use dmd -c to compile without linking and then link manually with gcc <object-files> -shared <your flags> -o lib<name>.so.
> 
> I hope that helps,
> Christian

Hi Christian,

I gave it a try but I didn't succeed, maybe you could help me again:

First i created the file "square.d":
    export int squareIt(int i) {
        return i*i;
    }

I compiled and linked it with:
    dmd -c square.d
    gcc -shared -o libsquare.so libsquare.o

I copied the library to /usr/local/lib (where ld may find it)

Then i created another file just containing the function declaration
("libsquare.d"):
    export int squareIt(int i);

The next step was writing a little sample app ("app.d"):
    import std.stdio;
    // now the important line: import the lib:
    import libsquare;

    void main(char[][] args) {
        writefln("4*4 = %d", squareIt(4));
    }

I tried to compile it this way:
    dmd app.d libsquare.d -L-lsquare

But this gave me an error message:
    gcc app.o libsquare.o -o app -m32 -lphobos -lm -Xlinker -lsquare
    app.o: In function '_Dmain':
    app.d:(.gnu.linkonce.t_Dmain+0xa): undefined reference to
'_imp__D9libsquare8squareItFiZi'
    collect2: ld returned 1 exit status
    --- errorlevel 1

As I'm new to shared objects under linux, I don't know how to proceed right now.


Nicolai

On Mon, 08 Jan 2007 21:18:32 +0100rochus <rochus@rochus.net> wrote:

> Christian Kamm wrote:

> I compiled and linked it with:
>     dmd -c square.d
>     gcc -shared -o libsquare.so libsquare.o
> 
> I copied the library to /usr/local/lib (where ld may find it)
> ...

You must run /sbin/ldconfig, to update ld caches.

-- 
Witold Baryluk
MAIL: baryluk@smp.if.uj.edu.pl, baryluk@mpi.int.pl
JID: movax@jabber.autocom.pl

Witold Baryluk wrote:
> On Mon, 08 Jan 2007 21:18:32 +0100rochus <rochus@rochus.net> wrote:
> 
> 
> You must run /sbin/ldconfig, to update ld caches.
> 

Sorry but that's not true. As long as the path (in this case, /usr/local/lib) is somewhere noted within ld.so.conf this path will be searched when a user wants to link against a library.

Nevertheless, I gave it a try and called ldconfig - it didn't work.

best regards,
Nicolai

> I gave it a try but I didn't succeed, maybe you could help me again:

Two things:
First, remove the 'export'. For me, it doesn't work with it.
Second, you defined a square.squareIt in your libsquare.so, but try to access it as libsquare.squareIt. Either put a 'module libsquare;' statement in square.d or use D's interface files: dmd -H should create such a file from your square.d. Then the compiler will use it when compiling with dmd app.d -L-lsquare.

Cheers,
Christian

Christian Kamm wrote:
>> I gave it a try but I didn't succeed, maybe you could help me again:
> 
> Two things:
> First, remove the 'export'. For me, it doesn't work with it.
> Second, you defined a square.squareIt in your libsquare.so, but try to
> access it as libsquare.squareIt. Either put a 'module libsquare;'
> statement in square.d or use D's interface files: dmd -H should create
> such a file from your square.d. Then the compiler will use it when
> compiling with dmd app.d -L-lsquare.
> 
> Cheers,
> Christian


Hi Christian and: Thank you!

After omitting "export" and renaming everything to "libsquare.d", it worked.

cheers!
Nicolai