Process and Thread Functions

This topic describes the process and thread functions.

Process Functions

The following functions are used with processes.

FunctionDescription
CreateProcess Creates a new process and its primary thread.
CreateProcessAsUser Creates a new process and its primary thread. The new process runs in the security context of the user represented by the specified token.
CreateProcessWithLogonW Creates a new process and its primary thread. The new process then runs the specified executable file in the security context of the specified credentials (user, domain, and password).
CreateProcessWithTokenW Creates a new process and its primary thread. The new process runs in the security context of the specified token.
ExitProcess Ends the calling process and all its threads.
FlushProcessWriteBuffers Flushes the write queue of each processor that is running a thread of the current process.
FreeEnvironmentStrings Frees a block of environment strings.
GetCommandLine Retrieves the command-line string for the current process.
GetCurrentProcess Retrieves a pseudo handle for the current process.
GetCurrentProcessId Retrieves the process identifier of the calling process.
GetCurrentProcessorNumber Retrieves the number of the processor the current thread was running on during the call to this function.
GetEnvironmentStrings Retrieves the environment block for the current process.
GetEnvironmentVariable Retrieves the value of the specified variable from the environment block of the calling process.
GetExitCodeProcess Retrieves the termination status of the specified process.
GetGuiResources Retrieves the count of handles to graphical user interface (GUI) objects in use by the specified process.
GetLogicalProcessorInformation Retrieves information about logical processors and related hardware.
GetPriorityClass Retrieves the priority class for the specified process.
GetProcessAffinityMask Retrieves a process affinity mask for the specified process and the system affinity mask for the system.
GetProcessGroupAffinity Retrieves the processor group affinity of the specified process.
GetProcessHandleCount Retrieves the number of open handles that belong to the specified process.
GetProcessId Retrieves the process identifier of the specified process.
GetProcessIdOfThread Retrieves the process identifier of the process associated with the specified thread.
GetProcessIoCounters Retrieves accounting information for all I/O operations performed by the specified process.
GetProcessMitigationPolicy Retrieves mitigation policy settings for the calling process.
GetProcessPriorityBoost Retrieves the priority boost control state of the specified process.
GetProcessShutdownParameters Retrieves shutdown parameters for the currently calling process.
GetProcessTimes Retrieves timing information about for the specified process.
GetProcessVersion Retrieves the major and minor version numbers of the system on which the specified process expects to run.
GetProcessWorkingSetSize Retrieves the minimum and maximum working set sizes of the specified process.
GetProcessWorkingSetSizeEx Retrieves the minimum and maximum working set sizes of the specified process.
GetProcessorSystemCycleTime Retrieves the cycle time each processor in the specified group spent executing deferred procedure calls (DPCs) and interrupt service routines (ISRs).
GetStartupInfo Retrieves the contents of the STARTUPINFO structure that was specified when the calling process was created.
IsImmersiveProcess Determines whether the process belongs to a Windows Store app.
NeedCurrentDirectoryForExePath Determines whether the current directory should be included in the search path for the specified executable.
OpenProcess Opens an existing local process object.
QueryFullProcessImageName Retrieves the full name of the executable image for the specified process.
QueryProcessAffinityUpdateMode Retrieves the affinity update mode of the specified process.
QueryProcessCycleTime Retrieves the sum of the cycle time of all threads of the specified process.
SetEnvironmentVariable Sets the value of an environment variable for the current process.
SetPriorityClass Sets the priority class for the specified process.
SetProcessAffinityMask Sets a processor affinity mask for the threads of a specified process.
SetProcessAffinityUpdateMode Sets the affinity update mode of the specified process.
SetProcessMitigationPolicy Sets the mitigation policy for the calling process.
SetProcessPriorityBoost Disables the ability of the system to temporarily boost the priority of the threads of the specified process.
SetProcessRestrictionExemption Exempts the calling process from restrictions preventing desktop processes from interacting with the Windows Store app environment. This function is used by development and debugging tools.
SetProcessShutdownParameters Sets shutdown parameters for the currently calling process.
SetProcessWorkingSetSize Sets the minimum and maximum working set sizes for the specified process.
SetProcessWorkingSetSizeEx Sets the minimum and maximum working set sizes for the specified process.
TerminateProcess Terminates the specified process and all of its threads.

 

Process Enumeration Functions

The following functions are used to enumerate processes.

FunctionDescription
EnumProcesses Retrieves the process identifier for each process object in the system.
Process32First Retrieves information about the first process encountered in a system snapshot.
Process32Next Retrieves information about the next process recorded in a system snapshot.
WTSEnumerateProcesses Retrieves information about the active processes on the specified terminal server.

 

Thread Functions

The following functions are used with threads.

FunctionDescription
AttachThreadInput Attaches the input processing mechanism of one thread to that of another thread.
CreateRemoteThread Creates a thread that runs in the virtual address space of another process.
CreateRemoteThreadEx Creates a thread that runs in the virtual address space of another process and optionally specifies extended attributes such as processor group affinity.
CreateThread Creates a thread to execute within the virtual address space of the calling process.
ExitThread Ends the calling thread.
GetCurrentThread Retrieves a pseudo handle for the current thread.
GetCurrentThreadId Retrieves the thread identifier of the calling thread.
GetExitCodeThread Retrieves the termination status of the specified thread.
GetThreadGroupAffinity Retrieves the processor group affinity of the specified thread.
GetThreadId Retrieves the thread identifier of the specified thread.
GetThreadIdealProcessorEx Retrieves the processor number of the ideal processor for the specified thread.
GetThreadIOPendingFlag Determines whether a specified thread has any I/O requests pending.
GetThreadPriority Retrieves the priority value for the specified thread.
GetThreadPriorityBoost Retrieves the priority boost control state of the specified thread.
GetThreadTimes Retrieves timing information for the specified thread.
OpenThread Opens an existing thread object.
QueryIdleProcessorCycleTime Retrieves the cycle time for the idle thread of each processor in the system.
QueryThreadCycleTime Retrieves the cycle time for the specified thread.
ResumeThread Decrements a thread's suspend count.
SetThreadAffinityMask Sets a processor affinity mask for the specified thread.
SetThreadGroupAffinity Sets the processor group affinity for the specified thread.
SetThreadIdealProcessor Specifies a preferred processor for a thread.
SetThreadIdealProcessorEx Sets the ideal processor for the specified thread and optionally retrieves the previous ideal processor.
SetThreadPriority Sets the priority value for the specified thread.
SetThreadPriorityBoost Disables the ability of the system to temporarily boost the priority of a thread.
SetThreadStackGuarantee Sets the stack guarantee for the calling thread.
Sleep Suspends the execution of the current thread for a specified interval.
SleepEx Suspends the current thread until the specified condition is met.
SuspendThread Suspends the specified thread.
SwitchToThread Causes the calling thread to yield execution to another thread that is ready to run on the current processor.
TerminateThread Terminates a thread.
ThreadProc An application-defined function that serves as the starting address for a thread.
TlsAlloc Allocates a thread local storage (TLS) index.
TlsFree Releases a TLS index.
TlsGetValue Retrieves the value in the calling thread's TLS slot for a specified TLS index.
TlsSetValue Stores a value in the calling thread's TLS slot for a specified TLS index.
WaitForInputIdle Waits until the specified process is waiting for user input with no input pending, or until the time-out interval has elapsed.

 

Process and Thread Extended Attribute Functions

The following functions are used to set extended attributes for process and thread creation.

FunctionDescription
DeleteProcThreadAttributeList Deletes the specified list of attributes for process and thread creation.
InitializeProcThreadAttributeList Initializes the specified list of attributes for process and thread creation.
UpdateProcThreadAttribute Updates the specified attribute in the specified list of attributes for process and thread creation.

 

WOW64 Functions

The following functions are used with WOW64.

FunctionDescription
IsWow64Message Determines whether the last message read from the current thread's queue originated from a WOW64 process.
IsWow64Process Determines whether the specified process is running under WOW64.
Wow64SuspendThread Suspends the specified WOW64 thread.

 

Job Object Functions

The following functions are used with job objects.

FunctionDescription
AssignProcessToJobObject Associates a process with an existing job object.
CreateJobObject Creates or opens a job object.
IsProcessInJob Determines whether the process is running in the specified job.
OpenJobObject Opens an existing job object.
QueryInformationJobObject Retrieves limit and job state information from the job object.
SetInformationJobObject Set limits for a job object.
TerminateJobObject Terminates all processes currently associated with the job.
UserHandleGrantAccess Grants or denies access to a handle to a User object to a job that has a user-interface restriction.

 

Thread Pool Functions

The following functions are used with thread pools.

FunctionDescription
CallbackMayRunLong Indicates that the callback may not return quickly.
CancelThreadpoolIo Cancels the notification from the StartThreadpoolIo function.
CloseThreadpool Closes the specified thread pool.
CloseThreadpoolCleanupGroup Closes the specified cleanup group.
CloseThreadpoolCleanupGroupMembers Releases the members of the specified cleanup group, waits for all callback functions to complete, and optionally cancels any outstanding callback functions.
CloseThreadpoolIo Releases the specified I/O completion object.
CloseThreadpoolTimer Releases the specified timer object.
CloseThreadpoolWait Releases the specified wait object.
CloseThreadpoolWork Releases the specified work object.
CreateThreadpool Allocates a new pool of threads to execute callbacks.
CreateThreadpoolCleanupGroup Creates a cleanup group that applications can use to track one or more thread pool callbacks.
CreateThreadpoolIo Creates a new I/O completion object.
CreateThreadpoolTimer Creates a new timer object.
CreateThreadpoolWait Creates a new wait object.
CreateThreadpoolWork Creates a new work object.
DestroyThreadpoolEnvironment Deletes the specified callback environment. Call this function when the callback environment is no longer needed for creating new thread pool objects.
DisassociateCurrentThreadFromCallback Removes the association between the currently executing callback function and the object that initiated the callback. The current thread will no longer count as executing a callback on behalf of the object.
FreeLibraryWhenCallbackReturns Specifies the DLL that the thread pool will unload when the current callback completes.
InitializeThreadpoolEnvironment Initializes a callback environment.
IsThreadpoolTimerSet Determines whether the specified timer object is currently set.
LeaveCriticalSectionWhenCallbackReturns Specifies the critical section that the thread pool will release when the current callback completes.
QueryThreadpoolStackInformation Retrieves the stack reserve and commit sizes for threads in the specified thread pool.
ReleaseMutexWhenCallbackReturns Specifies the mutex that the thread pool will release when the current callback completes.
ReleaseSemaphoreWhenCallbackReturns Specifies the semaphore that the thread pool will release when the current callback completes.
SetEventWhenCallbackReturns Specifies the event that the thread pool will set when the current callback completes.
SetThreadpoolCallbackCleanupGroup Associates the specified cleanup group with the specified callback environment.
SetThreadpoolCallbackLibrary Ensures that the specified DLL remains loaded as long as there are outstanding callbacks.
SetThreadpoolCallbackPersistent Specifies that the callback should run on a persistent thread.
SetThreadpoolCallbackPool Sets the thread pool to be used when generating callbacks.
SetThreadpoolCallbackPriority Specifies the priority of a callback function relative to other work items in the same thread pool.
SetThreadpoolCallbackRunsLong Indicates that callbacks associated with this callback environment may not return quickly.
SetThreadpoolStackInformation Sets the stack reserve and commit sizes for new threads in the specified thread pool.
SetThreadpoolThreadMaximum Sets the maximum number of threads that the specified thread pool can allocate to process callbacks.
SetThreadpoolThreadMinimum Sets the minimum number of threads that the specified thread pool must make available to process callbacks.
SetThreadpoolTimer Sets the timer object. A worker thread calls the timer object's callback after the specified timeout expires.
SetThreadpoolWait Sets the wait object. A worker thread calls the wait object's callback function after the handle becomes signaled or after the specified timeout expires.
StartThreadpoolIo Notifies the thread pool that I/O operations may possibly begin for the specified I/O completion object. A worker thread calls the I/O completion object's callback function after the operation completes on the file handle bound to this object.
SubmitThreadpoolWork Posts a work object to the thread pool. A worker thread calls the work object's callback function.
TpInitializeCallbackEnviron Initializes a callback environment for the thread pool.
TpDestroyCallbackEnviron Deletes the specified callback environment. Call this function when the callback environment is no longer needed for creating new thread pool objects.
TpSetCallbackActivationContext Assigns an activation context to the callback environment.
TpSetCallbackCleanupGroup Associates the specified cleanup group with the specified callback environment.
TpSetCallbackFinalizationCallback Indicates a function to call when the callback environment is finalized.
TpSetCallbackLongFunction Indicates that callbacks associated with this callback environment may not return quickly.
TpSetCallbackNoActivationContext Indicates that the callback environment has no activation context.
TpSetCallbackPersistent Specifies that the callback should run on a persistent thread.
TpSetCallbackPriority Specifies the priority of a callback function relative to other work items in the same thread pool.
TpSetCallbackRaceWithDll Ensures that the specified DLL remains loaded as long as there are outstanding callbacks.
TpSetCallbackThreadpool Assigns a thread pool to a callback environment.
TrySubmitThreadpoolCallback Requests that a thread pool worker thread call the specified callback function.
WaitForThreadpoolIoCallbacks Waits for outstanding I/O completion callbacks to complete and optionally cancels pending callbacks that have not yet started to execute.
WaitForThreadpoolTimerCallbacks Waits for outstanding timer callbacks to complete and optionally cancels pending callbacks that have not yet started to execute.
WaitForThreadpoolWaitCallbacks Waits for outstanding wait callbacks to complete and optionally cancels pending callbacks that have not yet started to execute.
WaitForThreadpoolWorkCallbacks Waits for outstanding work callbacks to complete and optionally cancels pending callbacks that have not yet started to execute.

 

The following functions are part of the original thread pooling API.

FunctionDescription
BindIoCompletionCallback Associates the I/O completion port owned by the thread pool with the specified file handle. On completion of an I/O request involving this file, a non-I/O worker thread will execute the specified callback function.
QueueUserWorkItem Queues a work item to a worker thread in the thread pool.
RegisterWaitForSingleObject Directs a wait thread in the thread pool to wait on the object.
UnregisterWaitEx Waits until one or all of the specified objects are in the signaled state or the time-out interval elapses.

 

Thread Ordering Service Functions

The following functions are used with the thread ordering service.

FunctionDescription
AvQuerySystemResponsiveness Retrieves the system responsiveness setting used by the multimedia class scheduler service.
AvRtCreateThreadOrderingGroup Creates a thread ordering group.
AvRtCreateThreadOrderingGroupEx Creates a thread ordering group and associates the server thread with a task.
AvRtDeleteThreadOrderingGroup Deletes the specified thread ordering group created by the caller.
AvRtJoinThreadOrderingGroup Joins client threads to a thread ordering group.
AvRtLeaveThreadOrderingGroup Enables client threads to leave a thread ordering group.
AvRtWaitOnThreadOrderingGroup Enables client threads of a thread ordering group to wait until they should execute.

 

Multimedia Class Scheduler Service Functions

The following functions are used with the multimedia class scheduler service.

FunctionDescription
AvRevertMmThreadCharacteristics Indicates that a thread is no longer performing work associated with the specified task.
AvSetMmMaxThreadCharacteristics Associates the calling thread with the specified tasks.
AvSetMmThreadCharacteristics Associates the calling thread with the specified task.
AvSetMmThreadPriority Adjusts the thread priority of the calling thread relative to other threads performing the same task.

 

Fiber Functions

The following functions are used with fibers.

FunctionDescription
ConvertFiberToThread Converts the current fiber into a thread.
ConvertThreadToFiber Converts the current thread into a fiber.
ConvertThreadToFiberEx Converts the current thread into a fiber.
CreateFiber Allocates a fiber object, assigns it a stack, and sets up execution to begin at the specified start address.
CreateFiberEx Allocates a fiber object, assigns it a stack, and sets up execution to begin at the specified start address.
DeleteFiber Deletes an existing fiber.
FiberProc An application-defined function used with the CreateFiber function.
FlsAlloc Allocates a fiber local storage (FLS) index.
FlsFree Releases an FLS index.
FlsGetValue Retrieves the value in the calling fiber's FLS slot for a specified FLS index.
FlsSetValue Stores a value in the calling fiber's FLS slot for a specified FLS index.
IsThreadAFiber Determines whether the current thread is a fiber.
SwitchToFiber Schedules a fiber.

 

NUMA Support Functions

The following functions provide NUMA support.

FunctionDescription
AllocateUserPhysicalPagesNuma Reserves or commits a region of memory within the virtual address space of the specified process, and specifies the NUMA node for the physical memory.
GetLogicalProcessorInformation Retrieves information about logical processors and related hardware.
GetNumaAvailableMemoryNode Retrieves the amount of memory available in the specified node.
GetNumaAvailableMemoryNodeEx Retrieves the amount of memory that is available in the specified node as a USHORT value.
GetNumaHighestNodeNumber Retrieves the node that currently has the highest number.
GetNumaNodeNumberFromHandle Retrieves the NUMA node associated with the underlying device for a file handle.
GetNumaNodeProcessorMask Retrieves the processor mask for the specified node.
GetNumaNodeProcessorMaskEx Retrieves the processor mask for the specified NUMA node as a USHORT value.
GetNumaProcessorNode Retrieves the node number for the specified processor.
GetNumaProcessorNodeEx Retrieves the node number of the specified logical processor as a USHORT value.
GetNumaProximityNode Retrieves the node number for the specified proximity identifier.
GetNumaProximityNodeEx Retrieves the node number as a USHORT value for the specified proximity identifier.
VirtualAllocExNuma Reserves or commits a region of memory within the virtual address space of the specified process, and specifies the NUMA node for the physical memory.

 

Processor Functions

The following functions are used with logical processors and processor groups.

FunctionDescription
GetActiveProcessorCount Returns the number of active processors in a processor group or in the system.
GetActiveProcessorGroupCount Returns the number of active processor groups in the system.
GetCurrentProcessorNumber Retrieves the number of the processor the current thread was running on during the call to this function.
GetCurrentProcessorNumberEx Retrieves the processor group and number of the logical processor in which the calling thread is running.
GetLogicalProcessorInformation Retrieves information about logical processors and related hardware.
GetLogicalProcessorInformationEx Retrieves information about the relationships of logical processors and related hardware.
GetMaximumProcessorCount Returns the maximum number of logical processors that a processor group or the system can have.
GetMaximumProcessorGroupCount Returns the maximum number of processor groups that the system can have.
QueryIdleProcessorCycleTime Retrieves the cycle time for the idle thread of each processor in the system.
QueryIdleProcessorCycleTimeEx Retrieves the accumulated cycle time for the idle thread on each logical processor in the specified processor group.

 

User-Mode Scheduling Functions

The following functions are used with user-mode scheduling (UMS).

FunctionDescription
CreateUmsCompletionList Creates a UMS completion list.
CreateUmsThreadContext Creates a UMS thread context to represent a UMS worker thread.
DeleteUmsCompletionList Deletes the specified UMS completion list. The list must be empty.
DeleteUmsThreadContext Deletes the specified UMS thread context. The thread must be terminated.
DequeueUmsCompletionListItems Retrieves UMS worker threads from the specified UMS completion list.
EnterUmsSchedulingMode Converts the calling thread into a UMS scheduler thread.
ExecuteUmsThread Runs the specified UMS worker thread.
GetCurrentUmsThread Returns the UMS thread context of the calling UMS thread.
GetNextUmsListItem Returns the next UMS thread context in a list of UMS thread contexts.
GetUmsCompletionListEvent Retrieves a handle to the event associated with the specified UMS completion list.
GetUmsSystemThreadInformation Queries whether the specified thread is a UMS scheduler thread, a UMS worker thread, or a non-UMS thread.
QueryUmsThreadInformation Retrieves information about the specified UMS worker thread.
SetUmsThreadInformation Sets application-specific context information for the specified UMS worker thread.
UmsSchedulerProc The application-defined UMS scheduler entry point function associated with a UMS completion list.
UmsThreadYield Yields control to the UMS scheduler thread on which the calling UMS worker thread is running.

 

Obsolete Functions

 

 

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