Parameter info popup
The Parameter Info popup shows the names of parameters in method and function calls. CLion automatically shows a popup with all available method signatures within 1 second (1000 milliseconds) after you type an opening bracket in the editor, or select a method from the suggestions list. 
You can explicitly invoke the popup if it has closed or if your IDE is configured not to show the popup automatically. To do so, press Ctrl+P (or click ).
Show full method or function signatures
By default, the parameter info popup shows simple signatures. You can configure the IDE to show full signatures that include method names and returned types.
In the Settings/Preferences dialog (Ctrl+Alt+S) , go to , and select the Show full method signatures checkbox.
Configure the parameter info popup
In the Settings/Preferences dialog (Ctrl+Alt+S) , go to .
In the Show the parameter info popup in ... milliseconds field, specify the time in milliseconds after which the popup should appear.
If you don't want the popup to appear automatically, clear the Show the parameter info popup in ... milliseconds checkbox.