#ifndef _NTLPCAPI_H

//
// General
//

/**
 * The NtRequestPort routine sends an asynchronous request message to a port.
 *
 * \param PortHandle Handle to the port object.
 * \param RequestMessage Pointer to the message to be sent.
 * \return NTSTATUS Successful or errant status.
 */
NTSYSCALLAPI
NTSTATUS
NTAPI
NtRequestPort(
    _In_ HANDLE PortHandle,
    _In_reads_bytes_(RequestMessage->u1.s1.TotalLength) PPORT_MESSAGE RequestMessage
    );

#endif
View code on GitHub

#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwRequestPort(
    _In_ HANDLE PortHandle,
    _In_reads_bytes_(RequestMessage->u1.s1.TotalLength) PPORT_MESSAGE RequestMessage
    );

#endif
View code on GitHub