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IOCTL(2)                  FreeBSD System Calls Manual                 IOCTL(2)

NAME
     ioctl -- control device

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/ioctl.h>

     int
     ioctl(int d, unsigned long request, ...);

DESCRIPTION
     The ioctl() function manipulates the underlying device parameters of spe-
     cial 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.

     The third argument to ioctl is traditionally named char *argp.  Most uses
     of ioctl in FreeBSD 3.0 however, require the third argument to be a
     caddr_t or an int.

     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.

     [EFAULT]           argp points outside the process's allocated address
                        space.

SEE ALSO
     execve(2), fcntl(2), intro(4), tty(4)

HISTORY
     An ioctl() function call appeared in Version 7 AT&T UNIX.

FreeBSD 4.10                   December 11, 1993                  FreeBSD 4.10

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | HISTORY

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