NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

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

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

     dev_t
     make_dev_alias(dev_t pdev, const char *fmt, ...);

     void
     destroy_dev(dev_t dev);

     void
     dev_depends(dev_t pdev, dev_t cdev);

DESCRIPTION    [Toc]    [Back]

     The make_dev() function creates a dev_t structure for a new device.  If
     DEVFS is available, it is also notified of the presence of the new
     device.  The device will be owned by uid, with the group ownership as
     gid, and with the name as specified in name.  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
	   #endif

     The make_dev_alias() function takes the returned dev_t 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 destroy_dev() function takes the returned dev_t 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
     between 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.

SEE ALSO    [Toc]    [Back]

     devfs(5)

HISTORY    [Toc]    [Back]

     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 function
 dev_depends() first appeared in FreeBSD 5.0.


FreeBSD 5.2.1			 May 27, 2001			 FreeBSD 5.2.1