JNI problem when calling a native library that loads another native library
- by TheEnemyOfQuality
I've got a bit of an odd problem. I have a project in C++ that's basically a wrapper for a third party DLL like this:
MyLibrary
--loads DLL_A
----loads DLL_B
I load DLL_A with LoadLibrary(), wrap several of its functions and generate my own DLL. I've tested this in a C++ project and a C# project. Both do everything they're supposed to do: load DLL_A, make a couple of function calls, and indirectly load DLL_B. The problem is when I build a DLL for java and make the calls through JNI. Everything runs like it should (no java.lang.UnsatisfiedLinkError), but when it comes time for DLL_A to load DLL_B it doesn't work.
From debugging, the loading of DLL_B happens on a function call in DLL_A that takes a callback. When called from Java, this function call seems to fail (the function pointer is fine and the actual call goes off without a hitch), and I get an odd pop-up window saying DLL_B failed to load, and my program is left waiting for a callback that never happens. I can explicitly load DLL_B just fine (both from Java and from C++) and I've checked every possible path, path variable, and tried placing the dlls everywhere to see if it could be looking somewhere funny. I'm pretty sure it's not a path problem.
Ultimately I don't know how DLL_A is loading DLL_B and I can't figure out why everything works fine in C++ and C#, but not in Java. I'm absolutely flummoxed. It could still be something specific to my setup (although I've looked as hard as I can look), but I'm throwing this scenario out there to see if anyone has run into a similar problem.
-Dave
