Unable to delete temporary DLL on Windows due to AccessViolationException

[phrack]

This issue is alive and well on every version of Windows: PatternConsulting#10.

[vonnieda]

If someone can come up with working fix for this, I'd be happy to integrate it :) Otherwise it will take a while until I can find some time to do this work on Windows.

[phrack]

My project can probably spend some time on a PR for this since it's really annoying for our users. Packaging binaries for Windows/Linux/Mac less so.

[vonnieda]

That would be awesome! I am planning to work on new binaries soon - just swamped with a cross country move right now and don't have time.

[phrack]

I just did that two weeks ago. I understand. I will check into OpenCV 3.1 stability too.

[phrack]

I've done a little bit of experimenting here and using a custom classloader that will get garbage collected, as the other repo issue suggests, just isn't going to be reliable. You can't guarantee when the garbage collector will actually run even with System.gc or how extensive the collection will be. In fact, System.gc, which is the only real illusion of control over garbage collection, doesn't even have to be implemented by a JVM.

I am going to propose a formalization of a solution I use in my project that uses this OpenCV package:

1. On Windows, prepend the folder created to hold the OpenCV binaries with opencv_ so that it's easy to find.
2. On Windows, do not try to delete the folder on shutdown.
3. On Windows, on startup look for folders that start with opencv_ and try to delete them otherwise the drive fills up with temporary OpenCV instances. If the delete fails, log it but move on without an exception. Failure to delete could simply mean another application on the same system is using the library.

[vonnieda]

Note: The JNA loader does something similar, but takes it a step further by adding a marker indicating which file should be deleted. I like this method and we should adopt it: https://github.com/java-native-access/jna/blob/master/src/com/sun/jna/Native.java#L1192

[mgineer85]

hi, just looked through the project and found an commit addressing the isse described here and I in openpnp/#699:
4697860#diff-cc2450ddb977c98e67b0eaa70c4aaa92R372

the commit was merged but I can't find the code in the local copy my eclipse is using. why is this?

this error prevents the junit-tests on windows to fail and abort early ...

[vonnieda]

Believe this was fixed in #9. If still experiencing please reopen.