IOCTL
NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS CONFORMING TO SEE ALSO
ioctl - control device
int ioctl(int d, int request,...)
The ioctl function manipulates the underlying device parameters of special files. In particular, many operating characteristics of character special files (e.g. terminals) may be controlled with ioctl requests. The argument d must be an open file descriptor.
An ioctl request has encoded in it whether the argument is an in parameter or out parameter, and the size of the argument argp in bytes. Macros and defines used in specifying an ioctl request are located in the file .
Usually, on success zero is returned. A few ioctls use the return value as an output parameter and return a nonnegative value on success. On error, -1 is returned, and errno is set appropriately.
No single standard. Arguments, returns, and semantics of ioctl(2) vary according to the device driver in question (the call is used as a catch-all for operations that don't cleanly fit the Unix stream I/O model). See ioctl_list(2) for a list of many of the known ioctl calls. The ioctl function call appeared in Version 7 AT&T Unix.
execve(2), fcntl(2), ioctl_list(2), mt(4), sd(4), tty(4), netdevice(7), socket(7)
26 pages link to ioctl(2):