ioctl(2)                   DG/UX 4.30                    ioctl(2)



     NAME
          ioctl - Control device.

     SYNOPSIS
          #include <sys/ioctl.h>

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

     PARAMETERS
          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 will accept 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.

     ACCESS CONTROL
          None.




     Licensed material--property of copyright holder(s)         Page 1

     ioctl(2)                   DG/UX 4.30                    ioctl(2)



     RETURN VALUE
          0              Completed successfully.


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

     EXCEPTIONS
          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
          The related manual sections:  stty(1),
          exec(2), fcntl(2), socket(2),
          termio(7).

























     Licensed material--property of copyright holder(s)         Page 2