Applications typically use the IOCTL interface to carry out selected Microsoft® MS-DOS® system functions, to obtain information about a device, or to carry out input and output (I/O) operations that are not available through standard Win32 functions.
This article describes the device IOCTL interface, explains how to use the interface in applications, and describes how to implement the interface in virtual devices (VxDs). For information about the device IOCTL interface for other operating systems that support the Win32 API, see the documentation included in the Microsoft Platform Software Development Kit (SDK).