How to deal with large uploads (no error message received)?

Assume I have a form that allows to upload large files together with short strings. The post method is used for the upload.

Problems arise when the uploaded files are larger than the maximum upload file limit because it seems to be that I do not get an error message. And I have no idea how to detect that something went wrong.

The controller's method to deal with the form is correctly called. When inspecting inside the controller's method a couple of $this->request->getPost('...') results I get NULL for all inspected variables: for the large uploaded file and for the short strings.

I also made a var dump of $this->request. It can be seen that the small short strings and the large uploaded file exist in the body of request. But the post and get arrays as well as the files array are empty.

Does anybody have a suggestion how to deal with this issue?