What does the exclamation in purple mean?

CodePudding user response：

These purple warnings are runtime warnings.

They usually occur because you have updated something on a background thread when it should be updated on the main thread. For instance you might have a titleLabel that you update in a completion handler from a network request and you haven't bumped the update to the main thread. (Or something)

They are used for other things too. Like if you have potential hanging threads etc...

They can also be custom warnings from third party frameworks (if they have been written that way).

https://www.pointfree.co/blog/posts/70-unobtrusive-runtime-warnings-for-libraries

You can see what is behind the purple warning by clicking on it and it will explain where in the code is causing the error and what the error it.