RtlIpv4StringToAddressExW - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTRTL_H

NTSYSAPI
NTSTATUS
NTAPI
RtlIpv4StringToAddressExW(
    _In_ PCWSTR AddressString,
    _In_ BOOLEAN Strict,
    _Out_ PIN_ADDR Address,
    _Out_ PUSHORT Port
    );

#endif

View code on GitHub

This function is documented in Windows SDK.