|IOCTL(2)||System Calls Manual||IOCTL(2)|
ioctl — control
unsigned long request, ...);
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
The argument fildes must be an open file
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 ⟨sys/ioctl.h⟩.
If an error has occurred, a value of -1 is returned and errno is set to indicate the error.
ioctl() will fail if:
ioctl() function call appeared in
Version 7 AT&T UNIX.
|December 11, 1993||BSD 4|