#ifndef _NTEXAPI_H
#if (PHNT_MODE != PHNT_MODE_KERNEL)

//
// Thread execution
//

/**
 * The NtDelayExecution routine suspends the current thread until the specified condition is met.
 *
 * @param Alertable The function returns when either the time-out period has elapsed or when the APC function is called.
 * @param DelayInterval The time interval for which execution is to be suspended, in milliseconds.
 * - A value of zero causes the thread to relinquish the remainder of its time slice to any other thread that is ready to run.
 * - If there are no other threads ready to run, the function returns immediately, and the thread continues execution.
 * - A value of INFINITE indicates that the suspension should not time out.
 * @return NTSTATUS Successful or errant status. The return value is STATUS_USER_APC when Alertable is TRUE, and the function returned due to one or more I/O completion callback functions.
 * @remarks Note that a ready thread is not guaranteed to run immediately. Consequently, the thread will not run until some arbitrary time after the sleep interval elapses,
 * based upon the system "tick" frequency and the load factor from other processes.
 * @see https://learn.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-sleepex
 */
NTSYSCALLAPI
NTSTATUS
NTAPI
NtDelayExecution(
    _In_ BOOLEAN Alertable,
    _In_ PLARGE_INTEGER DelayInterval
    );

#endif
#endif
View code on GitHub

#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwDelayExecution(
    _In_ BOOLEAN Alertable,
    _In_ PLARGE_INTEGER DelayInterval
    );

#endif
View code on GitHub