#ifndef _NTEXAPI_H
#if (PHNT_MODE != PHNT_MODE_KERNEL)

//
// UMS
//

/**
 * The NtUmsThreadYield routine yields control to the user-mode scheduling (UMS) scheduler thread on which the calling UMS worker thread is running.
 * Note: As of Windows 11, user-mode scheduling is not supported. All calls fail with the error STATUS_NOT_SUPPORTED.
 *
 * \param SchedulerParam Optional handle to the keyed event object. If NULL, the default keyed event is used.
 * \return NTSTATUS Successful or errant status.
 * \sa https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-umsthreadyield
 */
NTSYSCALLAPI
NTSTATUS
NTAPI
NtUmsThreadYield(
    _In_ PVOID SchedulerParam
    );

#endif
#endif
View code on GitHub

#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwUmsThreadYield(
    _In_ PVOID SchedulerParam
    );

#endif
View code on GitHub