DLLNotFoundException, trying to build bundle from .a library on OSX

Question

Hi all, I think I've met with a tricky problem.

I am on Mac OS Lion and I want to use Xcode 4 to build a bundle plugin for Unity Pro. The c code that I want to reuse is a bunch of .h and .c files that are supposed to be build by the make tools. I tried to build a Cocoa bundle with the C source files but failed. I then tried to use the .a library that make builds and I build that .a file into a bundle in Xcode. This time the build succeeded but when I was trying to call a function defined in the C source code, Unity gives me a runtime DLLNotFoundException.

Can someone please help me?

Here is detailed description of what I did:

I built a Cocoa bundle. The only effective component is a library called libccn.a so I guess in theory whatever function defined in the header ccn.h should be available for me after I imported the plugin. This is the definition of the function I called in ccn.h file: int ccn_run(struct ccn *h, int timeout);
I put the bundle in Unity's Plugin folder

This is my C# script

using UnityEngine; using System; using System.Collections; using System.Runtime.InteropServices;

public class PluginScript : MonoBehaviour {

  [StructLayout(LayoutKind.Auto)]
     public struct CCN
     {
     }
     
     [DllImport("CCNxB")]
     public static extern int ccn_run(ref CCN ccn, int timeout);
     
     void Start () {
         CCN ccn = new CCN();
         ccn_run(ref ccn, 1);
     }
 }

Here is a summary of my questions:

I thought Unity can't use .a libraries directly, am I right?
Can Unity use bundles built from .a libraries? Has anyone done that before?
If Unity can recognize bundles built from .a library, could anyone give me some hint about what I am doing wrong now?

Many thanks in advance!

Answer 1

Best Answer

Answer by GameFreak · Mar 23, 2012 at 08:20 PM

Its gonna be a bit long so I ll just post it as an answer rather than a comment

Firstly, I am not an expert so I will try my best to understand and tell you how they have used it in the plugin.

They have the .a file here Assets --> Editor --> GameCenter --> libGameCenterPlugin.a

Then in Plugins-->GameCenter they have a c# script with several [DllImport ("__Internal")]

about which you can read here

http://unity3d.com/support/documentation/Manual/Plugins.html

Then finally they have given this instruction

Build After make Unity XCode project link project with library "Assets/Editor/GameCenter/ libGameCenterPlugin.a"

(basically just drag it into Xcode)

I dont know if I can help more.

I told you what I understood

IF YOU DO WANT THE C# SCRIPT GIVE ME YOUR EMAIL. Even though it has nothing it is copyrighted and I dont want to get into trouble by posting it here.

heers

Rishab.

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CherryQu · Mar 23, 2012 at 09:38 PM 0

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Also I don't quite understand the instruction they gave (Build After make Unity XCode project link project with library "Assets/Editor/GameCenter/ libGameCenterPlugin.a")

You said you dragged the .a library into Xcode. But are you supposed to build an Xcode project? Isn't the library already in Unity? I thought if the static library is already in Unity and they already have a C# script that imports it, you won't need to build any Xcode project...

So could you tell me more about that? Thanks a lot!

GameFreak · Mar 24, 2012 at 06:52 AM 0

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Tickmark my answer so that the question is closed.

I have sent you email lets talk there.

CherryQu · Mar 24, 2012 at 07:10 AM 0

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alright~ I ticked :)

DLLNotFoundException, trying to build bundle from .a library on OSX

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IF YOU DO WANT THE C# SCRIPT GIVE ME YOUR EMAIL. Even though it has nothing it is copyrighted and I dont want to get into trouble by posting it here.

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