How to handle file closing errors in C?

How to handle file closing errors in C? I’m working on an ASP.NET web application using this contact form framework on Windows 2000. We’ve implemented a helper function with it to understand and handle some error occurences for a new user. And it handles everything properly. I noticed I was using a function not a variable “onClientLoad()”; in my view. It is enough to show what error occurence and if anything else the error. Now that I’m implementing both functions together I have a few issues: A controller isn’t shown the errors and if it is null return false What if I have a form button with a label and a submit button? If it is null it shouldn’t show the error here https://i.stack.imgur.com/F2Bvz.png Here is my view code: