Input functions disable input from system devices, take control of the system devices, or define special actions that Windows takes when an application receives input from a system device. (The system devices are the mouse, the keyboard, and the timer.) The following list briefly describes each input function:
| Function | Description | |
| EnableWindow | Enables and disables mouse and keyboard input throughout the application. | |
| GetActiveWindow | Returns a handle to the active window. | |
| GetCapture | Returns a handle to the window with the mouse capture. |
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| GetCurrentTime | Retrieves the current Windows time. | |
| GetDoubleClickTime | Retrieves the current double-click time for the mouse. | |
| GetFocus | Retrieves the handle of the window that currently owns the input focus. | |
| GetTickCount | Returns the number of timer ticks recorded since the system was booted. | |
| IsWindowEnabled | Determines whether the specified window is enabled for mouse and keyboard input. | |
| KillTimer | Kills the specified timer event. | |
| ReleaseCapture | Releases mouse input and restores normal input processing. |
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| SetActiveWindow | Makes a window the active window. | |
| SetCapture | Causes mouse input to be sent to a specified window. | |
| SetDoubleClickTime | Sets the double-click time for the mouse. | |
| SetFocus | Assigns the input focus to a specified window. | |
| SetSysModalWindow | Makes the specified window a system modal window. | |
| SetTimer | Creates a system-timer event. | |
| SwapMouseButton | Reverses the meaning of left and right mouse buttons. |