Passing a struct from c# to c++ on Android

I'm trying to pass a struct into a method of a native library (this library works in windows DLL)

the values of the struct are set before the method is called

but when the initial method in the C, the struct's value are nil or zero - as though it were passed an unpopulated struct

`AudioSourceMetaData` is the struct and is the same definition in both c# c/c++
`meta` is populated on the c# but unpopulated in c/c++

Code (C/C++):

1.  
2. // unitybridge.h - just has the headers
3. ...
4. int addFileToPlaylist(AudioSourceMetaData* meta);
5. ...
6. extern "C" {
7.     int addFileToPlaylist(UnityBridge* _unitybridge, AudioSourceMetaData* meta);
8. }...

Code (C/C++):

1.  
2. // unitybridge.cpp -
3.  
4. int UnityBridge::addFileToPlaylist(AudioSourceMetaData* meta) {
5.  
6.    MetaDataAudioFile* audioFile = new MetaDataAudioFile;
7.    audioFile->setValue(*meta);
8.    playlist.add(audioFile);
9.    int idx = playlist.indexOf(audioFile);
10.    createAudioAndMetaData(audioFile, idx);
11.    return idx;
12. }
13.  
14.    int addFileToPlaylist(UnityBridge* _unitybridge, AudioSourceMetaData* meta)
15.     {
16.         if (_unitybridge == nullptr)
17.         {
18.             return K_ERR_INT;
19.         }
20.         return _unitybridge->addFileToPlaylist(meta);
21.     }

any thoughts? am I missing something here?

 

Not sure, but if you Google for "Passing a struct from c# to c++" you find several articles that mention properly marshaling the data types, perhaps you've already seen these.

 

sorry for the delay in responding, @JeffDUnity3D and @Aurimas-Cernius - it was a bit of a marshalling issue on a boolean and I needed to use the `in` keyword, you both put me on the right track so thanks very much