GetRawInputData

GetRawInputData is a function in the Windows API that retrieves raw input data from a device. This data can include information from input devices such as keyboards, mice, and joysticks. The function is part of the Raw Input API, which provides a low-level interface for handling input devices.

To use GetRawInputData, an application typically first registers for raw input notifications using the RegisterRawInputDevices function. When a raw input event occurs, the system sends a WM_INPUT message to the application's window. The application then calls GetRawInputData within its message loop to retrieve the actual input data associated with that message.

The function requires a handle to the input data structure, which is typically obtained from the WM_INPUT message. It also takes a pointer to a buffer where the retrieved data will be stored, and the size of that buffer. If successful, GetRawInputData returns the number of bytes copied into the buffer.

The data retrieved by GetRawInputData is usually in the form of RAWINPUT structures, which contain details specific to the input device type. For example, a mouse input structure would contain information about movement and button clicks, while a keyboard input structure would contain scan codes and key states. This raw data allows applications to implement custom input handling logic, bypassing standard input processing if necessary.