ioctl - control device
Standard C Library (libc, -lc)
ioctl(int d, unsigned long request, void *argp);
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 <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:
[EBADF] d is not a valid descriptor.
[ENOTTY] d is not associated with a character special device.
[ENOTTY] The specified request does not apply to the kind of
object that the descriptor d references.
[EINVAL] request or argp is not valid.
mt(1), execve(2), fcntl(2), intro(4), tty(4)
An ioctl() function call appeared in Version 7 AT&T UNIX.
BSD December 11, 1993 BSD
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