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ioctl(2)			 System	Calls			      ioctl(2)

       ioctl - control device

       #include	<unistd.h>
       #include	<stropts.h>

       int ioctl(int fildes, int request, /* arg */ ...);

       The ioctl() function performs a variety of control functions on devices
       and STREAMS. For	non-STREAMS files, the	functions  performed  by  this
       call  are  device-specific control functions.  The request argument and
       an optional third argument with varying type are	 passed	 to  the  file
       designated by fildes and	are interpreted	by the device driver.

       For  STREAMS  files,  specific  functions  are performed	by the ioctl()
       function	as described in	streamio(7I).

       The fildes argument is an open file descriptor that refers to a device.
       The  request  argument selects the control function to be performed and
       depends on the device being addressed.  The arg argument	 represents  a
       third  argument	that has additional information	that is	needed by this
       specific	device to perform the requested	function. The data type	of arg
       depends upon the	particular control request, but	it is either an	int or
       a pointer to a device-specific data structure.

       In addition to device-specific and STREAMS functions, generic functions
       are  provided  by more than one device driver (for example, the general
       terminal	interface.)  See termio(7I)).

       Upon successful completion, the value returned depends upon the	device
       control function, but must be a non-negative integer.  Otherwise, -1 is
       returned	and errno is set to indicate the error.

       The ioctl() function will fail for any type of file if:

       EBADF	       The fildes argument is not a valid open	file  descrip-

       EINTR	       A signal	was caught during the execution	of the ioctl()

       EINVAL	       The STREAM  or  multiplexer  referenced	by  fildes  is
		       linked  (directly or indirectly)	downstream from	a mul-

       The ioctl() function will also fail if the device driver	detects	an er-
       ror.   In this case, the	error is passed	through	ioctl()	without	change
       to the caller. A	particular driver might	not have all of	the  following
       error cases. Under the following	conditions, requests to	device drivers
       may fail	and set	errno to indicate the error

       EFAULT	       The request argument requires a	data  transfer	to  or
		       from  a	buffer pointed to by arg, but arg points to an
		       illegal address.

       EINVAL	       The request or arg argument is not valid	for  this  de-

       EIO	       Some physical I/O error has occurred.

       ENOLINK	       The fildes argument is on a remote machine and the link
		       to that machine is no longer active.

       ENOTTY	       The fildes argument is not associated  with  a  STREAMS
		       device that accepts control functions.

       ENXIO	       The request and arg arguments are valid for this	device
		       driver, but the service requested can not be  performed
		       on this particular subdevice.

       ENODEV	       The  fildes  argument refers to a valid STREAMS device,
		       but the corresponding device driver  does  not  support
		       the ioctl() function.

       STREAMS errors are described in streamio(7I).

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       |Interface Stability	     |Standard			   |

       attributes(5), standards(5), streamio(7I), termio(7I)

SunOS 5.10			  15 Feb 1996			      ioctl(2)


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