Module opcode

Const functions for computing opcode values.

Linux’s headers define macros such as _IO, _IOR, _IOW, and _IOWR for defining ioctl values in a structured way that encode whether they are reading and/or writing, and other information about the ioctl. The functions in this module correspond to those macros.

If you’re writing a driver and defining your own ioctl numbers, it’s recommended to use these functions to compute them.

Functions

• from_components
  Create a new opcode from a direction, group, number, and size.
• none
  Create a new opcode from a group, a number, that uses no data.
• read
  Create a new reading opcode from a group, a number and the type of data.
• read_write
  Create a new reading and writing opcode from a group, a number and the type of data.
• write
  Create a new writing opcode from a group, a number and the type of data.