Help building JNI libraries

Question

All -
I'm currently working on a program which will solve Linear Programming problems. To do so, I would like to use the COIN-OR libraries which are implemented in C++ and I've decided to use JNI to do so. I've successfully compilied my java app, created my .h file using the javah -jni command and created and complited my c++ program. However, I get an error when attempting to build the library.
My CreateMPS.h file looks like this:
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class CreateMPS */
#ifndef IncludedCreateMPS
#define IncludedCreateMPS
#ifdef __cplusplus
extern "C" {
#endif
* Class: CreateMPS
* Method: clpSolve
* Signature: (Ljava/lang/String;)V
JNIEXPORT void JNICALL Java_CreateMPS_clpSolve
(JNIEnv *, jobject, jstring);
#ifdef __cplusplus
#endif
#endif
My ClpCaller.cpp, the implementation of this .h file looks like so:
#include <jni.h>
#include "CreateMPS.h"
#include "/Users/drew/COIN/Clp/include/ClpSimplex.hpp"
JNIEXPORT void JNICALL
Java_CreateMPS_clpSolve (JNIEnv *env, jobject obj, jstring prompt)
char buf[128];
const char *str = env->GetStringUTFChars(prompt, 0);
ClpSimplex model;
int status;
status = model.readMps(str);
if (!status) {
     model.primal();
env->ReleaseStringUTFChars(prompt, str);
Both the java app and the c++ app are compiled and I'm using the following command to build the libraries. I had success with this when building and running the HelloWorld sample on the JNI tutorial on this site. I am using OS X Tiger.
drew$ cc -dynamiclib -o libmps.jnilib ClpCaller.o -framework JavaVM
The name of my library is "mps". I get the following error when running the code:
ld: Undefined symbols:
__ZN10ClpSimplex6primalEii
__ZN10ClpSimplex7readMpsEPKcbb
__ZN10ClpSimplexC1Ev
__ZN10ClpSimplexD1Ev
__ZNSt8ios_base4InitC1Ev
__ZNSt8ios_base4InitD1Ev
___gxx_personality_v0
/usr/bin/libtool: internal link edit command failed
I am assuming these errors are coming from the COIN libraries I have included. Any help would be VERY appreciated!
Thanks,
Drew

Answer 1

>
ld: Undefined symbols:
__ZN10ClpSimplex6primalEii
__ZN10ClpSimplex7readMpsEPKcbb
__ZN10ClpSimplexC1Ev
__ZN10ClpSimplexD1Ev
__ZNSt8ios_base4InitC1Ev
__ZNSt8ios_base4InitD1Ev
___gxx_personality_v0
/usr/bin/libtool: internal link edit command failed
I am assuming these errors are coming from the COIN
libraries I have included. Any help would be VERY
appreciated!Building the library is entirely function of the other language. Java's involvement (in building the lib) is limited to producing the .h file. You will probably do better asking in a C++ forum.
However, a few possibilities:
- You should specify the external library to link with this, using -l option
- Or, if you want to load COIN at run time, tell link loader to not resolve all symbols at the time of linking. This might be handled by -dyanamiclib option.