IOCTL(2)						      BSD System Calls Manual							  IOCTL(2)

NAME
ioctl -- control device SYNOPSIS
#include <sys/ioctl.h> int ioctl(int d, unsigned long request, char *argp); DESCRIPTION
The ioctl() function manipulates the underlying device parameters of special files. In particular, many operating characteristics of charac- ter 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>. RETURN VALUES
If an error has occurred, a value of -1 is returned and errno is set to indicate the error. ERRORS
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. SEE ALSO
mt(1), cdio(1), chio(1), execve(2), fcntl(2), tty(4), intro(4) HISTORY
An ioctl() function call appeared in Version 7 AT&T UNIX. 4th Berkeley Distribution December 11, 1993 4th Berkeley Distribution