From: dtauritz AT WI DOT LeidenUniv DOT NL (D.R.Tauritz)
Organization: Leiden University,
              Dept. of Mathematics & Computer Science,
              The Netherlands
Subject: Re: coff format?
To: dj AT stealth DOT ctron DOT com (DJ Delorie)
Date: Mon, 31 Oct 1994 21:20:21 +0100 (MET)
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu, dliu AT faraday-gw DOT njit DOT edu

>> On Sun, 30 Oct 94 16:23:02 -0500, DJ Delorie wrote:
>>
>> Oh, there is an another question, I don't know how a program can use a
>> global variable in dll.
>
>I've never figured out how to manage that either, otherwise djgpp
>would have been using shared libraries a long time ago :-)

You can use a global variable in your client which was declared in your DLL
as well as a global variable in your DLL which was declared in your client.

An example of how to use a global variable in your client which was declared
in your DLL:

your_dll.h

  ...
  extern int var;
  ...

your_dll.c

  ...
  int var;
  ...

your_client.c

  #include "your_dll.h"

  int main()
  {
    ...
    int *var;
    ...
    var=(int *) dll_lookup(dll, "_var");
    ...
  }

An example of how to use a global variable in your DLL which was declared in
your client:

your_dll.c

  ...
  extern int *var;
  ...

your_client.c

  ...
  int *var;
  ...
  int main()
  {
    ...
    dll_register("_var",&var);
    ...
  }

Note that the first example defines a global variable of type int, while the
second example defines a global variable of type *int, just to prove both are
possible and of course to confuse you ;-)

Daniel

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