#ifndef _NTRTL_H
NTSYSAPI
SIZE_T
NTAPI
RtlSizeHeap(
_In_ HANDLE HeapHandle,
_In_ ULONG Flags,
_In_ PCVOID BaseAddress
);
View code on GitHubNo description available.
Kernel32.dll HeapSize maps directly to RtlSizeHeap. See Ms SDK for definition.