Quick Documentation popup is a universal tool to help you get more information on a code element at caret. CLion shows quick documentation in a popup on mouseover automatically. Depending on the element you invoke it for, the popup can include:
Function signature details.
Code documentation (either regular or Doxygen comments).
Inferred types, which is especially valuable for modern C++ that might lack explicit types. For example:
Macro replacements to help you better understand and debug nested macros (like Boost.Test or Catch macros). In the popup, you will see the final macro replacement properly formatted, with highlighted strings and keywords:
Disable quick documentation on mouseover
In the Settings/Preferences dialog (Ctrl+Alt+S), go to and clear the Show quick documentation on hover checkbox.
You can also click in the popup and disable the Show on Mouse Move option.
In this case, to view documentation for a symbol at caret, press Ctrl+Q or clickfrom the main menu.
Click in the popup to change the font size, display the quick documentation toolbar, or go to the source code. Press Ctrl+Q to switch between the popup and the tool window.