xref: /freebsd/share/man/man9/device_get_softc.9 (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
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31.Dd August 2, 2005
32.Dt DEVICE_GET_SOFTC 9
33.Os
34.Sh NAME
35.Nm device_get_softc
36.Nd access driver private instance variables
37.Sh SYNOPSIS
38.In sys/param.h
39.In sys/bus.h
40.Ft void *
41.Fn device_get_softc "device_t dev"
42.Sh DESCRIPTION
43Return the driver-specific state of
44.Fa dev .
45The softc is automatically allocated and zeroed when the device is
46attached.
47The softc is also initialized and present when a device is probed,
48but is subject to caveats as described in
49.Xr DEVICE_PROBE 9 .
50The size of the allocation is determined by the device's
51.Vt driver_t
52information used to define the driver.
53The softc typically encapsulates the state of this instance of the
54device.
55.Pp
56Driver writers are discouraged from using their own softc management
57mechanisms.
58Driver writers should not copy such mechanisms found in drivers in the
59tree that predate this function.
60.Sh RETURN VALUES
61The pointer to the driver-specific instance variable is returned.
62.Sh SEE ALSO
63.Xr device 9 ,
64.Xr DEVICE_PROBE 9 ,
65.Xr device_set_softc 9 ,
66.Xr driver 9
67.Sh AUTHORS
68This manual page was written by
69.An Doug Rabson .
70