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MAKE_DEV(9)		 BSD Kernel Developer's	Manual		   MAKE_DEV(9)

     make_dev, make_dev_alias, destroy_dev, dev_depends	-- manage cdev's and
     DEVFS registration	for devices

     #include <sys/param.h>
     #include <sys/conf.h>

     struct cdev *
     make_dev(struct cdevsw *cdevsw, int minor,	uid_t uid, gid_t gid,
	 int perms, const char *fmt, ...);

     struct cdev *
     make_dev_alias(struct cdev	*pdev, const char *fmt,	...);

     destroy_dev(struct	cdev *dev);

     dev_depends(struct	cdev *pdev, struct cdev	*cdev);

     The make_dev() function creates a cdev structure for a new	device.	 If
     DEVFS is available, it is also notified of	the presence of	the new	de-
     vice.  The	device will be owned by	uid, with the group ownership as gid.
     The name is the expansion of fmt and following arguments as printf(9)
     would print it.  The name determines its path under /dev or other
     devfs(5) mount point and may contain slash	`/' characters to denote sub-
     directories.  The permissions of the file specified in perms are defined
     in	<sys/stat.h>:

	   #define S_IRWXU 0000700    /* RWX mask for owner */
	   #define S_IRUSR 0000400    /* R for owner */
	   #define S_IWUSR 0000200    /* W for owner */
	   #define S_IXUSR 0000100    /* X for owner */

	   #define S_IRWXG 0000070    /* RWX mask for group */
	   #define S_IRGRP 0000040    /* R for group */
	   #define S_IWGRP 0000020    /* W for group */
	   #define S_IXGRP 0000010    /* X for group */

	   #define S_IRWXO 0000007    /* RWX mask for other */
	   #define S_IROTH 0000004    /* R for other */
	   #define S_IWOTH 0000002    /* W for other */
	   #define S_IXOTH 0000001    /* X for other */

	   #define S_ISUID 0004000    /* set user id on	execution */
	   #define S_ISGID 0002000    /* set group id on execution */
	   #define S_ISVTX 0001000    /* sticky	bit */
	   #ifndef _POSIX_SOURCE
	   #define S_ISTXT 0001000

     The make_dev_alias() function takes the returned cdev from	make_dev() and
     makes another (aliased) name for this device.  It is an error to call
     make_dev_alias() prior to calling make_dev().

     The cdev returned by make_dev() and make_dev_alias() has two fields,
     si_drv1 and si_drv2, that are available to	store state.  Both fields are
     of	type void *.  These are	designed to replace the	minor argument to

     The destroy_dev() function	takes the returned cdev	from make_dev()	and
     destroys the registration for that	device.	 Do not	call destroy_dev() on
     devices that were created with make_dev_alias().

     The dev_depends() function	establishes a parent-child relationship	be-
     tween two devices.	 The net effect	is that	a destroy_dev()	of the parent
     device will also result in	the destruction	of the child device(s),	if any
     exist.  A device may simultaneously be a parent and a child, so it	is
     possible to build a complete hierarchy.


     The make_dev() and	destroy_dev() functions	first appeared in FreeBSD 4.0.
     The function make_dev_alias() first appeared in FreeBSD 4.1.  The func-
     tion dev_depends()	first appeared in FreeBSD 5.0.

BSD				  May 6, 2007				   BSD


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