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Message-ID:	<005401c2a47d$921fa590$ef47fea9@calvin>
From:	"Frank Traenkle" <frank AT traenkle-online DOT de>
To:	<cygwin AT cygwin DOT com>
Subject:	IBM Java 13 + JNI + Cygwin fails
Date:	Sun, 15 Dec 2002 22:04:34 +0100
MIME-Version:	1.0
X-Priority:	3
X-MSMail-Priority:	Normal
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Hi,

Calling a DLL under Cygwin from IBM Java13 via JNI fails if the DLL depends
on cygwin1.dll. I am using the following versions:

uname -a
CYGWIN_NT-5.1 CALVIN 1.3.17(0.67/3/2) 2002-11-27 18:54 i686 unknown

gcc-2 --version
2.95.3-10

java -version
java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0)
Classic VM (build 1.3.0, J2RE 1.3.0 IBM build cn130-20020124 (JIT enabled:
jitc)
)

You can reproduce this with HelloWorld.java:
<<<
class HelloWorld {
    public native void displayHelloWorld();

    static {
        System.loadLibrary("HelloWorld");
    }

    public static void main(String[] args) {
         new HelloWorld().displayHelloWorld();
    }
}
>>>EOF HelloWorld.java

HelloWorld.c: <<<
#include <windows.h>
#include <jni.h>
#include "HelloWorld.h"
#include <stdio.h>

JNIEXPORT void JNICALL Java_HelloWorld_displayHelloWorld(JNIEnv *env,
jobject obj)
{
    printf("Hello world!\n");
    return;
}
>>> EOF HelloWorld.c

HelloWorld.c I compiled with
gcc-2 -shared -I/cygdrive/c/Programme/IBM/Java13/include -Wl,--add-stdcall-a
lias -o HelloWorld.dll HelloWorld.c

"java -verbose -classpath . HelloWorld" crashes with the following output:
[Running static initializer for HelloWorld]
[Signaling in VM: java/lang/UnsatisfiedLinkError, message:
C:\Programme\IBM\Java
13\jre\bin\HelloWorld.dll: Can't find dependent libraries]
        at java.lang.ClassLoader$NativeLibrary.load(Native Method)
        at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1470)
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1346)
        at java.lang.Runtime.loadLibrary0(Runtime.java:766)
        at java.lang.System.loadLibrary(System.java:849)
        at HelloWorld.<clinit>(HelloWorld.java:15)
[Loaded java.lang.UnsatisfiedLinkError from
C:\Programme\IBM\Java13\jre\lib\rt.j
ar]
[Loading superclasses of java/lang/UnsatisfiedLinkError]
[Preparing java/lang/UnsatisfiedLinkError]
[Loaded java.lang.ClassLoader$4 from C:\Programme\IBM\Java13\jre\lib\rt.jar]
[Loading superclasses of java/lang/ClassLoader$4]
[Preparing java/lang/ClassLoader$4]
[Signaling in VM: java/lang/UnsatisfiedLinkError, message:
C:\Programme\IBM\Java
13\bin\HelloWorld.dll: Can't find dependent libraries]
        at java.lang.ClassLoader$NativeLibrary.load(Native Method)
        at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1470)
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1358)
        at java.lang.Runtime.loadLibrary0(Runtime.java:766)
        at java.lang.System.loadLibrary(System.java:849)
        at HelloWorld.<clinit>(HelloWorld.java:15)

Please note there are no JVM shutdown messages. Cygwin1.dll is in %PATH%.
HelloWorld.dll can be loaded fine from other clients such as a MS Visual C++
with MFC.

If I add -mno-cygwin when compiling, HelloWorld.dll is loaded and invoked
just fine. But I need the cygwin1.dll for my project.

What can I do?

Frank






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