Class OrtEnv

The singleton class OrtEnv contains the process-global ONNX Runtime environment. It sets up logging, creates system wide thread-pools (if Thread Pool options are provided) and other necessary things for OnnxRuntime to function.

Create or access OrtEnv by calling the Instance() method. Instance() can be called multiple times. It would return the same instance.

CreateInstanceWithOptions() provides a way to create environment with options. It must be called once before Instance() is called, otherwise it would not have effect.

If the environment is not explicitly created, it will be created as needed, e.g., when creating a SessionOptions instance.

Inheritance

Object

CriticalFinalizerObject

SafeHandle

OrtEnv

Implements

IDisposable

Inherited Members

SafeHandle.handle

SafeHandle.Close()

SafeHandle.DangerousAddRef(Boolean)

SafeHandle.DangerousGetHandle()

SafeHandle.DangerousRelease()

SafeHandle.Dispose()

SafeHandle.Dispose(Boolean)

SafeHandle.SetHandle(IntPtr)

SafeHandle.SetHandleAsInvalid()

SafeHandle.IsClosed

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Microsoft.ML.OnnxRuntime

Assembly: Microsoft.ML.OnnxRuntime.dll

Syntax

public sealed class OrtEnv : SafeHandle, IDisposable

Properties

EnvLogLevel

Get/Set log level property of OrtEnv instance Default LogLevel.Warning

Declaration

public OrtLoggingLevel EnvLogLevel { get; set; }

Property Value

Type	Description
OrtLoggingLevel	env log level

IsCreated

Provides visibility if singleton already been instantiated

Declaration

public static bool IsCreated { get; }

Property Value

Type	Description
Boolean

IsInvalid

Overrides SafeHandle.IsInvalid

Declaration

public override bool IsInvalid { get; }

Property Value

Type	Description
Boolean	returns true if handle is equal to Zero

Overrides

System.Runtime.InteropServices.SafeHandle.IsInvalid

Methods

CreateAndRegisterAllocator(OrtMemoryInfo, OrtArenaCfg)

Create and register an allocator to the OrtEnv instance so as to enable sharing across all sessions using the OrtEnv instance

OrtMemoryInfo instance to be used for allocator creation OrtArenaCfg instance that will be used to define the behavior of the arena based allocator

Declaration

public void CreateAndRegisterAllocator(OrtMemoryInfo memInfo, OrtArenaCfg arenaCfg)

Parameters

Type	Name	Description
OrtMemoryInfo	memInfo
OrtArenaCfg	arenaCfg

CreateInstanceWithOptions(ref EnvironmentCreationOptions)

Provides a way to create an instance with options. It throws if the instance already exists and the specified options not have effect.

Declaration

public static OrtEnv CreateInstanceWithOptions(ref EnvironmentCreationOptions options)

Parameters

Type	Name	Description
EnvironmentCreationOptions	options

Returns

Type	Description
OrtEnv

Exceptions

Type	Condition
OnnxRuntimeException	if the singleton has already been created

DisableTelemetryEvents()

Disable platform telemetry collection

Declaration

public void DisableTelemetryEvents()

EnableTelemetryEvents()

Enable platform telemetry collection where applicable (currently only official Windows ORT builds have telemetry collection capabilities)

Declaration

public void EnableTelemetryEvents()

GetAvailableProviders()

Queries all the execution providers supported in the native onnxruntime shared library

Declaration

public string[] GetAvailableProviders()

Returns

Type	Description
String[]	an array of strings that represent execution provider names

GetEpDevices()

Get the list of all execution provider and device combinations that are available. These can be used to select the execution provider and device for a session.

Declaration

public IReadOnlyList<OrtEpDevice> GetEpDevices()

Returns

Type	Description
IReadOnlyList<OrtEpDevice>

GetVersionString()

This function returns the onnxruntime version string

Declaration

public string GetVersionString()

Returns

Type	Description
String	version string

Instance()

Instantiates (if not already done so) a new OrtEnv instance with the default logging level and no other options. Otherwise returns the existing instance.

It returns the same instance on every call - OrtEnv is singleton

Declaration

public static OrtEnv Instance()

Returns

Type	Description
OrtEnv	Returns a singleton instance of OrtEnv that represents native OrtEnv object

RegisterExecutionProviderLibrary(String, String)

Register an execution provider library with the OrtEnv instance. A registered execution provider library can be used by all sessions created with the OrtEnv instance. Devices the execution provider can utilize are added to the values returned by GetEpDevices() and can be used in SessionOptions.AppendExecutionProvider to select an execution provider for a device.

Coming: A selection policy can be specified and ORT will automatically select the best execution providers and devices for the model.

Declaration

public void RegisterExecutionProviderLibrary(string registrationName, string libraryPath)

Parameters

Type	Name	Description
String	registrationName	The name to register the library under.
String	libraryPath	The path to the library to register.

ReleaseHandle()

Destroys native object

Declaration

protected override bool ReleaseHandle()

Returns

Type	Description
Boolean	always returns true

Overrides

System.Runtime.InteropServices.SafeHandle.ReleaseHandle()

UnregisterExecutionProviderLibrary(String)

Unregister an execution provider library from the OrtEnv instance.

Declaration

public void UnregisterExecutionProviderLibrary(string registrationName)

Parameters

Type	Name	Description
String	registrationName	The name the library was registered under.

Implements

System.IDisposable