RtlNumberGenericTableElementsAvl function (ntddk.h)

Article
10/21/2021

The RtlNumberGenericTableElementsAvl routine returns the number of elements in a generic table.

Syntax

NTSYSAPI ULONG RtlNumberGenericTableElementsAvl(
  [in] PRTL_AVL_TABLE Table
);

Parameters

[in] Table

Pointer to the generic table (RTL_AVL_TABLE). The table must have been initialized by calling RtlInitializeGenericTableAvl.

Return value

RtlNumberGenericTableElementsAvl returns the number of elements that are currently stored in the table.

Remarks

By default, the operating system uses splay trees to implement generic tables, but the RtlNumberGenericTableElementsAvl 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:

#define RTL_USE_AVL_TABLES 0

If RTL_USE_AVL_TABLES is not defined, you must use the AVL form of the generic table routines. For example, use the RtlNumberGenericTableElementsAvl routine instead of RtlNumberGenericTableElements. In the call to RtlNumberGenericTableElementsAvl, 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 RtlNumberGenericTableElementsAvl must be running at IRQL < DISPATCH_LEVEL if the caller-allocated memory for the generic table is pageable.

Requirements

Requirement	Value
Minimum supported client	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)