IoGetDeviceInterfaceAlias function

The IoGetDeviceInterfaceAlias routine returns the alias device interface of the specified device interface instance, if the alias exists.


NTSTATUS IoGetDeviceInterfaceAlias(
  PUNICODE_STRING SymbolicLinkName,
  const GUID      *AliasInterfaceClassGuid,
  PUNICODE_STRING AliasSymbolicLinkName



Pointer to the name of the device interface instance for which to retrieve an alias. The caller typically received this string from a call to IoGetDeviceInterfaces or in a PnP notification structure.


Pointer to a GUID specifying the interface class of the alias to retrieve.


Specifies a pointer to a NULL Unicode string. On successful return, AliasSymbolicLinkName.Buffer points to a string containing the name of the alias. The caller must free the Unicode string with RtlFreeUnicodeString when it is no longer needed.

Return Value

IoGetDeviceInterfaceAlias returns STATUS_SUCCESS if the call was successful. Possible error return values are described following.

Return code Description
Possibly indicates that there is no alias of the specified interface class.
Possibly indicates that there is no alias of the specified interface class.
Possibly indicates an invalid SymbolicLinkName or an invalid AliasClassGuid.


Device interfaces are considered aliases if they are exposed by the same underlying device and have identical interface reference strings, but are of different interface classes.

The SymbolicLinkName parameter specifies a device interface instance for a particular device, belonging to a particular interface class, with a particular reference string. IoGetDeviceInterfaceAlias returns another device interface instance for the same device and reference string, but of a different interface class, if it exists.

For example, the function driver for a fault-tolerant volume could register and set two device interfaces, one of the fault-tolerant-volume interface class and one of the volume interface class. Another driver could call IoGetDeviceInterfaceAlias with the symbolic link for one of the interfaces and ask whether the other interface exists by specifying its interface class.

Two device interfaces with NULL reference strings are aliases if they are exposed by the same underlying device and have different interface class GUIDs.

Callers of IoGetDeviceInterfaceAlias must be running at IRQL = PASSIVE_LEVEL in the context of a system thread.


Minimum supported client Available starting with Windows 2000.
Target Platform Universal
Header wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
Library NtosKrnl.lib
DLL NtosKrnl.exe
IRQL PASSIVE_LEVEL (see Remarks section)
DDI compliance rules PowerIrpDDis, HwStorPortProhibitedDDIs

See Also