From owner-freebsd-java  Wed Mar 15 15:44:18 2000
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Date: Wed, 15 Mar 2000 16:44:06 -0700 (MST)
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From: Nate Williams <nate@yogotech.com>
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To: Chad David <davidc@acns.ab.ca>
Cc: Keith Wong <keith@1connect.com>,
	freebsd-java <freebsd-java@FreeBSD.ORG>
Subject: Re: JNI and Shared Library
In-Reply-To: <Pine.BSF.4.21.0003151357100.34452-100000@lodge.guild.ab.ca>
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	<Pine.BSF.4.21.0003151357100.34452-100000@lodge.guild.ab.ca>
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> I do not completely understand all that you have said, but hopefully this
> will help (it may be more than you asked for):
> 
> Step 1) Java source
> 
> public class Beep {
> 		public static native void beep(int count);
> 	}
> 	static {
> 		System.loadLibrary("beep");
> 	}
> 
> 	public static void main(String args[]) {
> 		beep(4);
> 	}
> }
> 
> Step 2) Compile the class and generate header
> 
> 	javac Beep.java
> 	javah -jni Beep.class
> 
> Step 3) C Source
> 
> include <stdio.h>
> include <unistd.h>
> #include "Beep.h" /* generated file */
> 
> JNIEXPORT void JNICALL
> Beep_beep(JNIEnv *e, jclass c, jint count) {
> int i = (int)count;
> 
> 	for ( ; i > 0; i--) {
> 		printf("%c", 7);
> 		fflush(stdout);
> 		usleep(300000);
> 	}
> 	return;
> }
> 
> Step 4) Compile and link that C code
> 
> 	cc -Wall -c beep.c  -I(the paths for your env)

Make sure you compile with -fPIC for the compiler as well.

 	cc -fPIC -Wall -c beep.c  -I(the paths for your env)


> 	ld -Bshareable -fPIC -o libbeep.so beep.o
> 
> Step 5) Set your LD_LIBRARY_PATH
> 
> 	export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$PWD
> 
> Step 6) Run the program
> 
> 	java Beep
> 
> I hope this helps (and I didn't miss anything).

Great instructions Chad, thanks!


Nate


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