TCM_HITTEST message

Determines which tab, if any, is at a specified screen position. You can send this message explicitly or by using the TabCtrl_HitTest macro.

Parameters

wParam: Must be zero.
lParam: Pointer to a TCHITTESTINFO structure that specifies the screen position to test.

Returns the index of the tab, or -1 if no tab is at the specified position.

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Header	Commctrl.h