ioctl(2)                       DG/UX R4.11MU05                      ioctl(2)


NAME
       ioctl - control a device

SYNOPSIS
       #include <sys/ioctl.h>
       #include <unistd.h>

       int ioctl (fildes, command, argument)
       int fildes;
       int command;
       int argument;

   where:
       fildes    A valid, active file descriptor
       command   A device control command
       argument  A pointer to the argument for the control command

DESCRIPTION
       ioctl provides a variety of operations on descriptors.  fildes is an
       active, valid descriptor.  command is an I/O control command to be
       performed on fildes using argument as an argument.  Not all commands
       require an argument.

       The 88open BCS version of ioctl accepts values for command only as
       specified in the BCS.

       The following two commands apply to any open file.  In both cases,
       argument is ignored.

       FIOCLEX   Set the `close-on-exec' attribute of fildes.  This causes
                 the file to be closed upon execution of the exec operation.

       FIONCLEX  Clear the `close-on-exec' attribute of fildes.  This causes
                 the file to remain open across exec operations.

       All other commands invoke the type manager of the object to which
       fildes refers to perform the I/O control operation.  Usually, the
       object must be a character-special device.

       The commands, arguments, and error conditions for particular kinds of
       I/O are documented in: rmt(7) (magnetic tapes), streamio(7)
       (STREAMS), termio(7) (terminals).

ACCESS CONTROL
       None.

RETURN VALUE
       0      Completed successfully.

       -1     An error occurred.  errno is set to indicate the error.

DIAGNOSTICS
       Errno may be set to one of the following error codes:

       EBADF     fildes is not a valid, active descriptor.

       ENOTTY    fildes does not refer to a character-special device and
                 command only operates on character-special devices.

       EINVAL    command or argument is not valid.

       EINTR     The call was interrupted by a signal.

       Additional errors may be given by the type managers.

SEE ALSO
       stty(1), exec(2), fcntl(2), socket(2), rmt(7), streamio(7), st(7),
       termio(7).


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