The Quick Info option displays the complete declaration for any identifier in your code.
Move the mouse so that the cursor is over an identifier to display Quick Info for that identifier, which appears in a yellow pop-up box.
When you select a member from the List Members box, Quick Info also appears.
You can manually invoke Quick Info feature as follows:
On the Edit menu, click IntelliSense, and then click Quick Info.
Use the keyboard shortcut CTRL+K, CTRL+I.
Select the Quick Info toolbar button from the Text Editor toolbar.
If a function is overloaded, IntelliSense may not display information for all forms of the overload.
Quick Info can be turned off by default. To turn Quick Info off, deselect Enable automatic Quick Info tooltips from the C/C++ Options property page for the desired language. For more information, see Modifying IntelliSense Options.
Quick Info will also include any code comments that may be on the definition of the member. For more information, see Supplying XML Code Comments.