svDdmGetState(2K)

NAME | SYNOPSIS | API RESTRICTIONS | FEATURES | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO

NAME

svDdmGetState- enable the DDM client to get the state of the specified node

SYNOPSIS

#include <ddm/ddm.h>

KnError svDdmGetState(DevNode node, unsigned int *state);

API RESTRICTIONS

The function or functions documented here may not be used safely in all application contexts with all APIs provided in the ChorusOS 5.0 product.

See API(5FEA) for details.

FEATURES

DDM

DESCRIPTION

The svDdmGetState() call enables the client of the DDM to get the state value of the specified node.

There are in fact two independent state values that are returned in the state variable: the availability state, and the run state (see DDM(5FEA)).

In order to supply the two independent state values, the state variable will contain, on return, a bitmask that we can describe by the following logical equation:

state = (DDM_AVSTATE_ENABLED / DDM_AVSTATE_DISABLED) |
        (DDM_RUNSTATE_INACTIVE / DDM_RUNSTATE_OFFLINE / 
         DDM_RUNSTATE_ONLINE)

where: / = exclusive OR and | = inclusive OR

The availability state can be any one of the following:

DDM_AVSTATE_ENABLED

The normal state, where the device is able to activate a device driver to manage it, if required.

DDM_AVSTATE_DISABLED

The device is locked which means that no device driver can be started to manage it.

---

Note -

The availability state resembles a flag more than a request. For example, if you have an enabled, online device but its availability state is set to DDM_AVSTATE_DISABLED, its run state will not change. This only implies that when you stop the driver (set the device to DDM_RUNSTATE_INACTIVE), no new drivers will be subsequently authorized to start for the node.

---

The run state can be any of the following:

DDM_RUNSTATE_INACTIVE

The device is shutdown which means that there is no driver running to handle it. The only operation that can be performed in this situation is to set the device in the online or offline state.

DDM_RUNSTATE_OFFLINE

The device cannot perform any operations. However, it is ready to perform any requested diagnostics.

DDM_RUNSTATE_ONLINE

The device is ready to perform any of the operations that it is capable of. These operations include DDM operations (the DDM is a client of the device through its mngt DDI) and other operations that are available to a client connected to any other DDI exported by the device. In this state it is possible to obtain statistics on the I/O activity and perform a non-intrusive audit of the health of the device driver.

RETURN VALUES

Upon completion K_OK is returned if the state of the specified node has been successfully determined. Otherwise, a negative error code is returned which indicates why the svDdmGetState() call was unsuccessful.

ERRORS

K_EUNDEF

The specified node is not recognized as a manageable device.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving

SEE ALSO

svDdmOpen(2K), svDdmClose(2K), svDdmEnable(2K), svDdmDisable(2K), svDdmShutdown(2K), svDdmOffline(2K), svDdmOnline(2K), svDdmGetStats(2K), svDdmAudit(2K), svDdmDiag(2K), svDdmGetInfo(2K), DDM(5FEA)

ChorusOS 5.0  Last Revised December 2001

NAME | SYNOPSIS | API RESTRICTIONS | FEATURES | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO