Is it possible to write a static library in D and then use it in a program written in C? I've found instructions about using DLLs here on the website, but there is no mention about using static libraries instead.

Also, is it possible to use the same method on Linux, just with .a files instead? Or .so for that matter?

Of course!

dstatic.d:
module dstatic;

extern(C):

int add(int x, int y)
{
    return x + y;
}

Then compile with:
dmd -lib dstatic.d

driver.c:
#include "stdio.h"

int main()
{
    printf("add(4, 5) = %d", add(4, 5));
}

dmc driver.c dstatic.lib

driver.exe
> add(4, 5) = 9

The problem (on Windows), is that the static lib is in the OMF format, and modern tools like VC or MinGW won't be able to read those, because they use COFF instead. So you would have to convert from OMF to COFF.

But on Linux I think DMD uses the standard Linux object file format, so I don't think there's issues there. (AFAIK).

On 01/16/2011 03:34 PM, Andrej Mitrovic wrote:
> The problem (on Windows), is that the static lib is in the OMF format,
> and modern tools like VC or MinGW won't be able to read those, because
> they use COFF instead. So you would have to convert from OMF to COFF.
>
> But on Linux I think DMD uses the standard Linux object file format,
> so I don't think there's issues there. (AFAIK).

http://www.digitalmars.com/d/archives/digitalmars/D/learn/d_and_c_21526.html

it didn't work the last time I tried it

On 01/16/2011 05:04 PM, Ellery Newcomer wrote:
> On 01/16/2011 03:34 PM, Andrej Mitrovic wrote:
>> The problem (on Windows), is that the static lib is in the OMF format,
>> and modern tools like VC or MinGW won't be able to read those, because
>> they use COFF instead. So you would have to convert from OMF to COFF.
>>
>> But on Linux I think DMD uses the standard Linux object file format,
>> so I don't think there's issues there. (AFAIK).
>
> http://www.digitalmars.com/d/archives/digitalmars/D/learn/d_and_c_21526.html
>
>
> it didn't work the last time I tried it

hmm. take out the __gshared int, and add -lib to the dmd command, and it does work..

I've just realized I didn't even prototype the function in the C module. DMC doesn't warn about this, it seems. Not even with the -A (ANSI C) flag. It won't even warn me when I prototype the function and pass doubles instead of ints. Maybe I didn't enable all warnings? (I've used: dmc -wc -v2 -A).

Ah, I see, thanks! I'll try that.

While I don't have a problem with using DMC, but others who are willing to join my project might have one... Right now I'm using MinGW, so it would definitely be useful to know how to convert the libraries to the format it understands... Though from the looks of it people are having problems with that... coffimplib only does a COFF->OMF conversion, and not the other way round, right?

On 1/17/11, GreatEmerald <pastas4@gmail.com> wrote:
> Ah, I see, thanks! I'll try that.
>
> While I don't have a problem with using DMC, but others who are willing to
> join my
> project might have one... Right now I'm using MinGW, so it would definitely
> be
> useful to know how to convert the libraries to the format it understands...
> Though
> from the looks of it people are having problems with that... coffimplib only
> does
> a COFF->OMF conversion, and not the other way round, right?
>

There is no dedicated tool that can do it alone, but I think I've just figured out a way to do it, and I'll post it in the D general newsgroup.

Also make sure you use globals properly if you use them (shared, __gshared, etc.)

All right, it worked, when the D side is this:

module techborg;
import std.c.stdio;

extern(C):
    shared int ResultD;

    int Process(int Value)
    {
        printf("You have sent the value: %d\n", Value);
        ResultD = (Value % 5);
        return ResultD;
    }

However, if I wanted to use printf() from std.stdio, dmc can't link
the library any more and complains about undefined symbols:
techborg.lib
 Warning 140: Library probably needs FIXLIB
techborg.lib(techborg)
 Error 42: Symbol Undefined _D3std5stdio12__ModuleInfoZ

Also, what was that solution you found for converting OMF->COFF? I can't seem to find the post you mentioned.