Why i can't use BlueprintCallable in UFUNCTION

When I remove UFUNCIONT(BlueprintCallable), it runs well;
When I use it, there are some errors while compiling.
Why I can’t use it?

sorry for Chinese in ERROR LIST.

You should always check the Output Window, not the VS error list, as it’s stated in the documentation: Setting Up Visual Studio for Unreal Engine | Unreal Engine Documentation

As for your problem, it’s probably because there is no int16 support in Blueprints, only int32 (and int64 from 4.22).

It is the reason, thank you!

Glad that it worked!
Don’t forget to accept the answer for future Googlers :slight_smile: