Real-Time API Functions

This section contains a list of supported RTAPI functions.

RTAPI Function Name	Description
RtAcquireFastSemaphore	Places the thread into a busy wait state until the fast semaphore is released.
RtAllocateContiguousMemory	Allocates physically contiguous memory.
RtAllocateContiguousMemorySpecifyCache	Allocates a range of physically contiguous, cache-aligned memory.
RtAllocateLocalMemory	Allocates memory from the local pool or pool cache of the external allocation space of the current process.
RtAllocateLocalMemoryEx	Allocates memory from a pre-allocated RTSS local memory pool to avoid SRI activity if allocating memory from the Windows memory pool.
RtAllocateLockedMemory	Commits and locks the specified amount of memory to avoid page faults as the memory is used.
RtAtoi	Converts a given string value to an integer.
RtAttachInterrupt	Allows the user to associate an Interrupt Service Thread (IST) and Interrupt Service Routine (ISR) with a line-based or message-based hardware interrupt.
RtAttachShutdownHandler	Registers a stop notification handler function with RTSS. The handler function is called in its own thread when one of the system stop events occurs.
RtCancelTimer	Cancels the expiration of the indicated timer.
RtCloseHandle	Closes an open object handle.
RtCreateEvent	Creates a named or unnamed event object.
RtCreateMutex	Creates an RTSS mutex. A handle is returned to the newly created mutex object.
RtCreateProcess	Creates and starts a new RTSS process. The new RTSS process runs the specified RTSS executable file. RtCreateProcess is supported only in the Windows environment.
RtCreateSemaphore	Creates a named or unnamed semaphore object.
RtCreateSharedMemory	Creates a named region of physical memory that can be mapped by any process.
RtCreateTimer	Creates a timer associated with the specified clock, and returns a handle to the timer.
RtCreateTimerEx	Creates a timer associated with the specified clock, and returns a handle to the timer.
RtDeleteProcThreadAttributeList	Deletes the specified list of attributes for process and thread creation.
RtDeleteTimer	Deletes the timer specified by the given handle.
RtDisableInterrupts	In the Windows environment, RtDisableInterrupts disables all user-level interrupt handling for all interrupts to which the Windows process is attached. In an RTSS environment, RtDisableInterrupts disables all interrupts at the processor level including timer interrupts.
RtDisablePortIo	Disables direct I/O port access from user context.
RtEnableInterrupts	Enables user-level interrupt handling for all interrupts to which the process is attached.
RtEnablePortIo	Enables direct I/O port access from user context.
RtEnumProcesses	Retrieves the process identifier for each process object.
RtEnumProcessesEx	Retrieves the process identifier for each RTSS process object.
RtEnumProcessModules	Retrieves a handle for each module in a specified process.
RtEnumProxyProcesses	Enumerates proxy processes associated with Windows processes linked to RTAPI.
RtExpandMSpace	Expands the local pool of the specified MSpace by the size specified.
RtFreeContiguousMemory	Frees a previously allocated physically contiguous memory region.
RtFreeLocalMemory	Frees memory previously allocated by a call to RtAllocateLocalMemory or RtAllocateLocalMemoryEx.
RtFreeLockedMemory	Frees memory previously committed and locked by a call to RtAllocateLockedMemory.
RtGenerateEvent	Generates custom Monitoring Framework events.
RtGetBusDataByOffset	Obtains details, starting at the given offset, about a given slot on an I/O bus.
RtGetClockResolution	Obtains the resolution of the specified clock.
RtGetClockTime	Obtains the current value of the specified clock.
RtGetClockTimerPeriod	Obtains the minimum timer period of the specified clock. The RtGetClockTimecall delivers the clock time as 64-bit quantity of 100ns.
RtGetCountFastSemaphore	Returns the number of threads waiting on this fast semaphore. This information is useful when preparing for a manual release of the fast semaphore.
RtGetCurrentHalTimerPeriod	Returns the current HAL timer period value used by the Subsystem.
RtGetCurrentProcessorNumber	Returns the system-assigned number of the current processor on which the caller is running.
RtGetEnabledXStateFeature	Returns the highest feature for a specified XState feature set supported on the running processor and enabled by RTX64.
RtGetExitCodeProcess	Retrieves the termination status of the specified process.
RtGetFlushTLBTickMod	Allows a RTSS process to query the current flush TLB tick mod set by RtSetFlushTLBTickMod.
RtGetHalTimerPeriodCounts	Retrieves the APIC counts per RTX64 HAL timer period.
RtGetLicenses	Retrieves information about licenses installed on the system.
RtGetModuleBaseName	Retrieves the base name of a specified module.
RtGetModuleFileName	Retrieves the fully-qualified path for the file that contains the specified module.
RtGetModuleFileNameEx	Retrieves the fully-qualified path for the file that contains the specified module.
RtGetPciMsixFreeMessages	Returns a PCI device’s MSI-X free messages (the MSI-X table entries available for attaching messages).
RtGetPhysicalAddress	Returns the physical address for the virtual address of a contiguous physical memory buffer previously allocated by RtAllocateContiguousMemory. In the RTSS environment, this function applies to all memory allocation. In the Windows environment, it applies to contiguous memory allocation only.
RtGetProcessAffinityMask	Retrieves the process affinity mask for the specified RTSS process and the system affinity mask for RTSS.
RtGetProcessIdealProcessor	Retrieves the ideal processor for a given RTSS process handle.
RtGetProcessMSpace	Retrieves an MSpace descriptor of the external and internal allocation space for the specified RTSS process or system process.
RtGetProcessorInfo	Retrieves the number values for the lowest and highest RTSS processors.
RtGetProcessTimes	Retrieves timing information for the specified RTSS process.
RtGetProxyThreadPriority	Returns the priority value of the proxy thread associated with the specified Windows thread (can only be called by Windows applications linked with RTX64).
RtGetRDTCapability	Returns the system Resource Director Technology (RDT) allocation capability.
RtGetRtssTimeAsFileTime	Gets the current value for RTSS time.
RtGetRuntimeVersionEx	Retrieves the Runtime version of the installed RTX64 product.
RtGetSystemTimes	Retrieves an array of system timing information. On a multiprocessor system, values in each of the FILETIME structures will contain system timing information about the RTSS core.
RtGetThreadCLOS	Retrieves the Class of Services (CLOS) value of a specified thread.
RtGetThreadPriority	Returns the priority value for the specified thread.
RtGetThreadStack	Retrieves the thread stack parameters for an existing thread object.
RtGetThreadTimeQuantum	Gets the current time quantum, in milliseconds, for the specified thread. NOTE: This function is deprecated and will be removed from a future release. Use RtGetTimeQuantum.
RtGetThreadTimeQuantumEx	Gets the current time quantum, in microseconds, for the specified thread. NOTE: This function is deprecated and will be removed from a future release. Use RtGetTimeQuantum.
RtGetThreadTimes	Retrieves timing information for the specified RTSS thread. This function can only be called in RTSS processes.
RtGetTimeQuantum	Retrieves the time quantum, in milliseconds, of a specified thread.
RtGetTimer	Returns the remaining relative time until the next expiration of the specified timer.
RtInitializeFastSemaphore	Initializes a fast semaphore object.
RtInitializeProcThreadAttributeList	Initializes a specified list of attributes for process and thread creation.
RtIsAppRunnable	Allows RTSS applications to validate an application's RTSS signature.
RtIsDebuggerPresent	Determines whether a local real-time process is attached to the IntervalZero Real-Time Debugger.
RtIsDefaultLocalMemory	Returns the default memory allocation configuration (local or Windows) for the Subsystem and RTSS applications.
RtIsInRtss	Provides the ability to determine whether code is running in RTSS or Windows.
RtIsRuntimeLicensed	Verifies that a specified RTX64 Runtime is installed and has a valid license.
RtIsTcpStackLicensed	Verifies that a specified RTX64 RT-TCP/IP Stack component is installed and has a valid license.
RtMapMemory	Maps a range of physical memory addresses into the user's virtual address space.
RtMonitorChangeState	Transitions between monitoring session states.
RtMonitorControl	Performs various monitoring control operations.
RtMonitorEnableComponents	Transiently enables generation of monitor events by one or more RTX64 product components
RtMonitorGetEnabledComponents	Retrieves the transient configuration of RTX64 product components that currently have monitoring event generation enabled
RtMonitorGetMaxEventsInSession	Retrieves the transient value of the maximum number of events to collect in a monitoring session.
RtMonitorGetPreTriggerEventsToSave	Retrieves the transient value of the number of pre-trigger events to save in a monitor session. Pre-trigger events are events that occur before the event type(s) that triggers the start of a monitoring session.
RtMonitorSetCustomTriggers	Transiently sets the custom event types that will trigger the start of a monitoring session.
RtMonitorSetEvents	Enables or disables collection of events during a monitoring session.
RtMonitorSetMaxEventsInSession	Sets the transient value of the maximum number of events to collect in a monitoring session.
RtMonitorSetPreTriggerEventsToSave	Sets the transient value of the number of pre-trigger events to save in a monitor session. Pre-trigger events are events that occur before the event type(s) that triggers the start of a monitoring session.
RtMonitorSetTriggers	Transiently sets the event types that will trigger the start of a monitoring session.
RtOpenEvent	Returns a handle of an existing named event object.
RtOpenMutex	Returns a handle to the named RTSS mutex.
RtOpenProcess	Returns a handle to an existing process object.
RtOpenSemaphore	Returns a handle of an existing named semaphore object.
RtOpenSharedMemory	Opens a named physical-mapping object.
RtOpenThread	Opens an existing thread object and returns a handle to that thread object.
RtPrintf	Prints formatted output to the standard output stream or console window.
RtPulseEvent	Provides a single operation that sets (to signaled) the state of the specified event object and then resets it (to non-signaled) after releasing the appropriate number of waiting threads.
RtQueryComponent	Returns status information on installed Subsystem components.
RtQueryPciMsiCapability	Allows a user to query a PCI device and determine if the device has MSI or MSI-X capability. RtQueryPciMsiCapability is only supported in the RTSS environment. It cannot be called from a Windows application linked to RTX.
RtQueryPerformanceCounter	Retrieves the current value of the high-resolution performance counter (based on processor’s time-stamp counter, TSC).
RtQueryPerformanceFrequency	Retrieves the frequency of the high-resolution performance counter (based on processor’s time-stamp counter, TSC).
RtQueryProcessMSpace	Queries memory allocation space information in the specified process MSpace, including various summary statistics of its local pool and pool cache.
RtQueryProcessorVectorFreeCount	Queries the number of RTSS processor vectors (IDT vectors) currently available for attaching interrupts.
RtQuerySharedMemory	Retrieves shared memory information.
RtQuerySystemPerfCaps	Queries the performance capability of each logical processor for the specified ClassID.
RtQueryThreadPerfIdealProcessor	Queries the thread’s current Class ID, the performance ideal processor, the current performance capability of affinity logical processor, and the performance capability of each logical processor based on hardware feedback.
RtReadPortBufferUchar	Calls copy data from an I/O port to a buffer until the buffer has been filled using a number of bytes that you specify for each read operation.
RtReadPortBufferUlong	Calls copy data from an I/O port to a buffer until the buffer has been filled using a number of bytes that you specify for each read operation.
RtReadPortBufferUshort	Calls copy data from an I/O port to a buffer until the buffer has been filled using a number of bytes that you specify for each read operation.
RtReadPortUchar	Calls read data directly from an I/O port. Each function reads a different number of bytes of data.
RtReadPortUlong	Calls read data directly from an I/O port. Each function reads a different number of bytes of data.
RtReadPortUshort	Calls read data directly from an I/O port. Each function reads a different number of bytes of data.
RtReleaseAllFastSemaphore	Releases all threads waiting on the fast semaphore. Ensures that all waiting threads enter the ready-to-run state. Ensures that no new threads enter the busy wait state until all current waiters have become runnable.
RtReleaseFastSemaphore	Releases the specified count of threads waiting on the fast semaphore. If the number of waiting threads is less than the specified count, RtReleaseFastSemaphore will store the remaining count value and continue to release new threads that call RtAcquireFastSemaphore on this fast semaphore.
RtReleaseInterrupt	Releases an interrupt previously attached using RtAttachInterrupt. This breaks the association between a user's interrupt handling routine and the hardware interrupt.
RtReleaseMutex	Relinquishes ownership of an RTSS mutex.
RtReleaseSemaphore	Increases the count of the specified semaphore object by a specified amount.
RtReleaseShutdownHandler	Destroys the shutdown handler object created by RtAttachShutdownHandler.
RtResetEvent	Sets the state of the specified event object to non-signaled.
RtResetWatchdog	Resets the watchdog timer counter on the specified RTSS core(s).
RtSetBusDataByOffset	Sets bus-configuration data for a device on a dynamically configurable I/O bus with a published, standard interface.
RtSetClockTime	Sets the current value of the specified clock.
RtSetEvent	Sets the state of the specified event object to signaled.
RtSetFlushTLBTickMod	Allows a RTSS process to set the flush TLB tick mod.
RtSetHalTimerPeriodCounts	Sets the APIC counts per RTX64 HAL timer period.
RtSetProcessAffinityMask	Sets a processor affinity mask for the threads of the specified RTSS process.
RtSetProxyThreadPriority	Sets the proxy thread priority for the associated Windows thread, but will not change the Windows thread priority (can only be called by Windows applications linked with RTX64).
RtSetRtssTimeAsFileTime	Sets the new value for RTSS time.
RtSetThreadCLOS	Overwrites a thread’s implicit or default Class of Services (CLOS), which is based on its priority.
RtSetThreadPriority	Sets the priority value for the specified thread.
RtSetThreadTimeQuantum	Sets the time quantum for the specified thread. NOTE: This function is deprecated and will be removed from a future release. Use RtSetTimeQuantum.
RtSetThreadTimeQuantumEx	Sets the time quantum, in microseconds, for the specified thread. NOTE: This function is deprecated and will be removed from a future release. Use RtSetTimeQuantum.
RtSetTimeQuantum	Sets the time quantum, in milliseconds, of a specified thread.
RtSetTimer	Sets the expiration time and repeat interval on the specified timer.
RtSetTimerRelative	Sets the expiration time and repeat interval on the specified timer.
RtShrinkMSpace	Shrinks the local pool of the specified MSpace up to the size specified.
RtSleepEx	Suspends the current thread until the specified condition is met.
RtSleepFt	Suspends the current thread for the specified time.
RtSleepFtEx	Suspends execution of the current thread for a specified time period.
RtStartComponent	Starts the specified Subsystem component.
RtStopComponent	Stops the specified Subsystem component.
RtTerminateProcess	Terminates the specified process and all of its threads.
RtTranslateBusAddress	Translates a bus-specific address into the corresponding system logical address.
RtUnmapMemory	Releases a mapping made by a previous call to RtMapMemory.
RtUpdateProcThreadAttribute	Updates the specified attribute in a list of attributes for process and thread creation.
RtWaitForMultipleObjects	Allows a thread to wait on one of multiple objects to be signaled.
RtWaitForMultipleObjectsEx	Allows a thread to wait on one of multiple objects to be signaled with high granularity of time-out interval.
RtWaitForSingleObject	Allows a thread to wait on an object to be signaled.
RtWaitForSingleObjectEx	Allows a thread to wait on an object to be signaled with high granularity of time-out interval.
RtWPrintf	Prints formatted output to the standard output stream or console window.
RtWritePortBufferUchar	Calls copy data from a buffer to an I/O port until the buffer has been emptied using a number of bytes that you specify for each write operation.
RtWritePortBufferUlong	Calls copy data from a buffer to an I/O port until the buffer has been emptied using a number of bytes that you specify for each write operation.
RtWritePortBufferUshort	Calls copy data from a buffer to an I/O port until the buffer has been emptied using a number of bytes that you specify for each write operation.
RtWritePortUchar	Calls write data directly to an I/O port from a specified buffer. Each function writes a different number of bytes of data.
RtWritePortUlong	Calls write data directly to an I/O port from a specified buffer. Each function writes a different number of bytes of data.
RtWritePortUshort	Calls write data directly to an I/O port from a specified buffer. Each function writes a different number of bytes of data.
RtWtoi	Converts a given string value to an integer.

NOTE: The functions listed under #pragma deprecated in the real-time API, Rtapi.h, are actually unsupported, not deprecated. Listing them this way ensures that a warning appears in Visual Studio when a developer attempts to use an unsupported function in Visual Studio.

NOTE: Implicit TLS initializers/finalizers must not take too long to execute. While they are executing, any real-time APIs that create or destroy internal RTX64 Subsystem objects (e.g., threads, processes, mutexes, semaphores, open files, etc.) will block.