Crash when trying to present UIActivityViewController - objective-c

Question

I see a crash in Crashlytics than happens to my users sometimes. The crash happens when presenting UIActivityViewController in the last line of the following code:
NSData* snapShot = ... ;
UIActivityViewController *activityViewController = [[UIActivityViewController alloc] initWithActivityItems:[NSArray arrayWithObjects:activityTextsProvider, snapShot ,nil] applicationActivities:[NSArray arrayWithObjects:customActivityA, customActivityB, customActivityC, nullptr]];
activityViewController.excludedActivityTypes = [NSArray arrayWithObjects:UIActivityTypePrint, UIActivityTypeAssignToContact, UIActivityTypeMail, UIActivityTypeCopyToPasteboard, nil];
activityViewController.popoverPresentationController.sourceView = self.myButton;
activityViewController.popoverPresentationController.sourceRect = self.myButton.bounds;
activityViewController.completionWithItemsHandler = ^(NSString *activityType, BOOL completed, NSArray *returnedItems, NSError *activityError)
{
...
};
[self presentViewController:activityViewController animated:YES completion:nil];
I perform this in the main thread and unable to reproduce this crash locally. What could be the reason of this crash?
Edit: I changed nullptr to nil and the issue still happened. I managed to reproduce the issue: the crash happens only if before opening the activity controller i showed a UIMenuController. When creating UIActivityViewController it is not nil, but when presenting the controller i see the crash in the presentViewController line and the activity controller there is shown as nil

Answer 1

József addressed the use of nullptr in comments, and Fogh is spot-on that the actual crash log is important (please edit your question and post the full crash log), but I'd like to point out something else.
You're assuming your call to initialize activityViewController is succeeding. You should code defensively (by assuming everything that can fail probably will fail and testing for this at runtime). Wrap the rest of the configuration and presentation inside an if (activityViewController != nil) {} condition (you should probably have an else with proper error handling/reporting too) so you're properly detecting an all-out initialization failure for multiple reasons (like a misplaced nib, missing resource, etc.).
In your case, I think it's likely the initialization is failing because your class is doing something with a faulty array, as József's nullptr catch suggests. Perhaps you're using one or more pre-C++11 c libraries / compiling with a non-C11/gnu11 "C Language Dialect" build setting and nullptr is not equivalent to nil, leading to strange results in a supposed-to-be-nil-terminated array?
Note: If that turns out to be the case, I'll happily take an upvote but would rather József post his comment as an answer so you can give him proper credit. (Feel free to edit this request out of my answer if/when that happens.)