Sender: gianci AT educ DOT disi DOT unige DOT it
Message-ID: <36A6FDC4.687AF9C7@freemail.it>
Date: Thu, 21 Jan 1999 11:13:24 +0100
From: Junks <junks AT freemail DOT it>
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Newsgroups: comp.os.msdos.djgpp,comp.lang.java.help
To: djgpp AT delorie DOT com, robert DOT hoehne AT gmx DOT net
CC: Teun Burgers <burgers AT ecn DOT nl>
Subject: Re: Making a DLL with DJGPP for Java Native Interface
References: <36A483F9 DOT 38910023 AT freemail DOT it>
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Reply-To: djgpp AT delorie DOT com

Junks wrote:
> 
> I used with great profit in the past DJGPP to write programs which
> worked finely both under Win95/NT and under Linux. Now I have to use the
> algorithms which lie behind these programs within Java. I know that to
> avoid to rewrite them from scratch in Java I can use Java Native
> Interface. In Linux I had no problems, while I had them under Win95/NT
> in building a DLL using DJGPP + RSXNTDJ. I was unable to build a simple
> DLL containing a single function like this one:
> 
> int f( int x) { return ++x; }
> 
> I set up RSXNTDJ properly yet it seems something is missing. Maybe the
> definition file but I have never used them and I don't know the syntax.
> 
> I hope somebody could help me because I enjoyed using DJGPP and I would
> avoid to use other free compilers like Cygnus (I had problems in setting
> it up) or lccwin32 (which is not a C++ compiler).
> 
> Thanks in advance.

I fixed the problem. I downloaded a recent version of RSXNTDJ, RSX131
and eventually I succeeded in building a .DLL for JNI. The best option
resulted to be -no-rte (no run time).

In order the whole thing to work you have to do add the lines

#include <windows.h>
typedef long long __int64;

in the jdk\include\win32\jni_md.h file, otherwise it will not compile.

Moreover, I found out the way to build the .DLL within RHIDE, avoiding
the mess of the Makefile which sometimes refuse to work (due to a
strange message "Missing separator" while the Makefile is OK, somebody
knows why?) 

The steps to do are:

1) Add the line 

RHIDE_COMPILE..dll=$(RHIDE_COMPILE_LINK)

in the shared file rhide.env (which should be in the \share\rhide
subdirectory of DJGPP). Otherwise create it with that single line in the
directory where you work.

2) Add "-Zwin32 -Zdll -Zno-rte" in the Options-Compiler Options 

3) Specify the name of the library  in the Project-main target name. It
is crucial that the name has the .DLL extension otherwise it will not
work. Be sure  also that a file .def with the same name exists
containing a list of the functions which implement the Native methods
headed by the keyword EXPORTS.

That's all folk, now you can create a .DLL file for Java Native
Interface with DJGPP + RSXNTDJ + RHIDE. 

Junks, or Gianci (to be read jeeahnchee).