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ioctl(2)							      ioctl(2)

       ioctl - control device

       #include	<sys/ioctl.h>

       ioctl(d,	request, argp)
       int d, request;
       char *argp;

       The  call performs a variety of functions on open descriptors.  In par-
       ticular,	many operating characteristics of character special files (for
       example,	 terminals) can	be controlled with requests.  Certain requests
       operate on a  number  of	 device	 types.	 These	include	 informational
       requests, such as and The descriptions of various devices in the	Refer-
       ence Pages, Section 4: Special Files discuss how	applies	to them.  Also
       consult <sys/ioctl.h> for more information.

       An  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  request are located in the file

Return Values
       If an error has occurred, a value of -1 is returned, and	errno  is  set
       to indicate the error.

       The call	fails under the	following conditions:

       [EBADF]	      The d is not a valid descriptor.

       [ENOTTY]	      The d is not associated with a character special device.

       [ENOTTY]	      The specified request does not  apply  to	 the  kind  of
		      object which the descriptor d references.

       [EINVAL]	      The request or argp is not valid.

       [EFAULT]	      The  argp	 points	 to  memory  that  is  not part	of the
		      process' address space.

See Also
       execve(2), fcntl(2), devio(4), intro(4n), mu(4),	nbuf(4), tty(4)


Name | Syntax | Description | Return Values | Diagnostics | See Also

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