JNI on Mac OS X Undefined symbols error when linking

Question

I'm trying to compile a jni library for mac os x. My system is running Mountain Lion if that matters. I created a jni project in xcode and copied the source files into the project. It compiles well but had linking errors. Here is the error:

Undefined symbols for architecture x86_64:
  "_init_queue", referenced from:
      _floodfill in floodfill.o
  "_jumpPointSearch", referenced from:
      _Java_com_clashtune_pathfind_Pathfinder_jumpPointSearchNative in main.o
     (maybe you meant: _Java_com_clashtune_pathfind_Pathfinder_jumpPointSearchNative)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

What did I do wrong? It's having four source files main.c, floodfill.c, jumppointsearch.c and queue.c. I don't understand what they do since I'm not a C programmer. I'm just compiling them for a friend on this forum.

EDIT:

This is the project property page 'Build Phases' for this project.

enter image description here

Thanks.

@Dayalrai I just used the IDE. I don't know what is the command. — Sri Harsha Chilakapati, Oct 11 '13 at 08:19
@Dayalrai I don't get what you mean. I've added `JavaVM.framework` to the frameworks list and set the includes folder to the one that came with JDK. — Sri Harsha Chilakapati, Oct 11 '13 at 08:28
@Dayalrai I've added the screenshot of the `Build Phases` property page. — Sri Harsha Chilakapati, Oct 11 '13 at 08:34
Project -> Build Settings -> Find LLVM Compiler group -> C++ Standard Library. Aneways please have a look [here](http://stackoverflow.com/questions/18408531/xcode-build-failure-undefined-symbols-for-architecture-x86-64) too. — sandeep upadhyay, Oct 11 '13 at 08:42
@sandeepupadhyay Is it `libstdc++ (GNU C++ Standard Library)`? It is giving the same errors. — Sri Harsha Chilakapati, Oct 11 '13 at 08:45
Is there any Default option? Please try with that and let us know. — sandeep upadhyay, Oct 11 '13 at 08:45
@sandeepupadhyay It's giving the same results. From what I see in the code, `init_queue`, `floodfill` and `jumpPointSearch` are normal functions. — Sri Harsha Chilakapati, Oct 11 '13 at 08:48
Find the file'_init_queue','_floodfill' in your project and select it. Use the properties inspector (Apple-Option-1) to ensure that it's added to your target membership whatever that target may be. It will need have a tick next to the target. — sandeep upadhyay, Oct 11 '13 at 09:00
You added the framework, but you need to drag and drop it to the Link Binary With Libraries section under "Build Phases". So the framework was not correctly added to your project until now.Check it again. — sandeep upadhyay, Oct 11 '13 at 09:03
@sandeepupadhyay The source files has the tick as you said, but the tick is not present for header files. And for the `build phases` the framework is in the link binary with libraries section. I've included it in the screenshot. — Sri Harsha Chilakapati, Oct 11 '13 at 09:07
Thanks for the help everybody. The project is using Objective C for some reason. Changing it to C++ worked. — Sri Harsha Chilakapati, Oct 11 '13 at 10:02

score 0 · Answer 1 · answered Nov 07 '16 at 20:49

You can try with super simple sample code. All you need is a simple C code and Java class that will load library.

I suggest to take a look here:

http://jnicookbook.owsiak.org/recipe-No-001/

That's super simple Hello World application where all you have to do is to call simple C code:

JNIEXPORT void JNICALL Java_recipeNo001_HelloWorld_displayMessage
  (JNIEnv *env, jclass obj) {

  printf("Hello world!\n");

}

from Java code:

package recipeNo001;

public class HelloWorld {

  /* This is the native method we want to call */
  public static native void displayMessage();

  /* Inside static block we will load shared library */
  static {
    System.loadLibrary("HelloWorld");
  }

  public static void main(String[] args) {
    /* This message will help you determine whether
        LD_LIBRARY_PATH is correctly set
    */
    System.out.println("library: "
      + System.getProperty("java.library.path"));

    /* Call to shared library */
    HelloWorld.displayMessage();
  }
}

If you are using XCode, you should be able to use command line tools as well. Take a look here, how to check whether you have them installed:

http://jnicookbook.owsiak.org/introduction/

Have fun with JNI ;)

Thanks for the answer, but I already got this working. The error is that I have it setup with objective C as the language as default. All I had to do is to change it to C++ and it worked. — Sri Harsha Chilakapati, Nov 08 '16 at 02:41

JNI on Mac OS X Undefined symbols error when linking

1 Answers1