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28 .Dt BUS_CHILD_PRESENT 9
32 .Nd "ask the bus driver to see if this device is still really present"
39 .In machine/resource.h
41 .Fn bus_child_present "device_t dev"
45 function requests that the parent device driver of
48 hardware represented by
50 is still physically accessible at this time.
51 While the notion of accessible varies from bus to bus, generally
52 hardware that is not accessible cannot be accessed via the
54 methods that would otherwise be used to access the device.
56 This does not ask the question
57 .Dq does this device have children?
58 which can better be answered by
59 .Xr device_get_children 9 .
61 A zero return value indicates that the device is not present in the
63 A non-zero return value indicates that the device is present in the
64 system, or that the state of the device cannot be determined.
66 This is some example code.
67 It only calls stop when the
69 device is actually present.
70 .Bd -literal -offset indent
74 sc = device_get_softc(dev);
75 if (bus_child_present(dev))
82 This manual page was written by
83 .An Warner Losh Aq Mt imp@FreeBSD.org .