RtlLookupElementGenericTableAvl function

The RtlLookupElementGenericTableAvl routine searches a generic table for an element that matches the specified data.


NTSYSAPI PVOID RtlLookupElementGenericTableAvl(
  PVOID          Buffer



Pointer to the generic Adelson-Velsky/Landis (AVL) table (RTL_AVL_TABLE). The table must have been initialized by calling RtlInitializeGenericTableAvl.


A buffer of search data to pass to the CompareRoutine that was registered when RtlInitializeGenericTableAvl initialized the generic table. For more information, see the description of RtlInitializeGenericTableAvl.

Return Value

RtlLookupElementGenericTableAvl returns a pointer to the user data that is associated with the matching element in the generic table, or NULL if the generic table currently has no elements or if no matching element is found.


By default, the operating system uses splay trees to implement generic tables, but the RtlLookupElementGenericTableAvl routine only works with Adelson-Velsky/Landis (AVL) trees. To configure the generic table routines to use AVL trees instead of splay trees in your driver, insert the following define statement in a common header file before including Ntddk.h:


If RTL_USE_AVL_TABLES is not defined, you must use the AVL form of the generic table routines. For example, use the RtlLookupElementGenericTableAvl routine instead of RtlLookupElementGenericTable. In the call to RtlLookupElementGenericTableAvl, the caller must pass a RTL_AVL_TABLE table structure rather than RTL_GENERIC_TABLE.

Callers of the Rtl..GenericTableAvl routines are responsible for exclusively synchronizing access to the generic table. An exclusive fast mutex is the most efficient synchronization mechanism to use for this purpose.

Callers of RtlLookupElementGenericTableAvl must be running at IRQL < DISPATCH_LEVEL if either of the following conditions holds:

  • The caller-allocated memory at Table or at Buffer is pageable.
  • The caller-supplied CompareRoutine contains pageable code.


Windows version Available starting with Windows XP.
Target Platform Universal
Header ntddk.h (include Ntddk.h, Ntifs.h)
Library NtosKrnl.lib
DLL NtosKrnl.exe
IRQL "< DISPATCH_LEVEL (see Remarks section)"

See Also