I've been converting a program to D and been successful so far.
Interfacing
with C is not a big issue but,
I've been trying to make a D module for the
ncurses library which works well
except for the acs_map array.

I realize
that the ncurses library is not the most modular one and it's
stuffed with
macros but I have to use it.

The general problem is as follows: The ncurses
library header file defines an
external array pointer as follows:
extern
chtype *acs_map;

That array is filled by the library on run-time and contains
the terminal
character conversion map.
For now D seems unable to use because
it doesn't connect the D-symbol with the
library at link time, and instead
defines a new pointer type. Of course
accessing that results in a seg-fault.
To get around the problem I rename the acs_map pointer to sym_map and wrote a
small C function:

#include <ncurses.h>
extern chtype *sym_map;
int
initLibrary()
{
  sym_map = acs_map;
}

I compile it with C and link
everything together.
This seems to work, but I don't like the solution.
Question: How do I define an external pointer int D that is resolved at link
time?

Thanks
Jaap

"Jaap Geurts" <Jaap_member@pathlink.com> wrote in message news:cbdmv0$2pk2$1@digitaldaemon.com...
> Question: How do I define an external pointer int D that is resolved at
link
> time?

Easy. Create a module, call it foo.d:

    module foo;
    extern (C) char* sym_map;

Import foo.d and use sym_map. But don't link in foo.obj!

This technique is used in phobos' std.c.stdio for the _iob[] array.

In article <cc0hlv$9gv$3@digitaldaemon.com>, Walter says...
> 
>"Jaap Geurts"
<Jaap_member@pathlink.com> wrote in message
>news:cbdmv0$2pk2$1@digitaldaemon.com...
>> Question: How do I define an external pointer int D that is resolved at
>link
>> time?
> 
>Easy. Create a module, call it foo.d:
> 
>    module foo;
>    extern (C) char* sym_map;
> 
>Import foo.d and use sym_map. But don't link in foo.obj!
> 
>This technique is used in phobos' std.c.stdio for the _iob[] array.
> 

Thanks, Walter,

Yes, that works. After some extensive debuggin I also figured out that this
works:

extern (C)
{
  extern char sym_map[256];
}

Even if I link this code in it still works. If I remove the extern keyword it
doesn't. It that correct?

Forgot to mention: D is EXCELLENT. I've been waiting for the simplicity of
Java but be able to interface with and generate real executables.

Jaap