CLSCTX_INPROC_SERVER

The code that creates and manages objects of this class is a DLL that runs in the same process as the caller of the function specifying the class context.

CLSCTX_INPROC_HANDLER

The code that manages objects of this class is an in-process handler. This is a DLL that runs in the client process and implements client-side structures of this class when instances of the class are accessed remotely.

CLSCTX_LOCAL_SERVER

The EXE code that creates and manages objects of this class runs on same machine but is loaded in a separate process space.

CLSCTX_INPROC_SERVER16

Deprecated.

CLSCTX_REMOTE_SERVER

A remote machine context. The LocalServer32 or LocalService code that creates and manages objects of this class is run on a different machine.

CLSCTX_INPROC_HANDLER16

Deprecated.

CLSCTX_RESERVED1

Deprecated.

CLSCTX_RESERVED2

Deprecated.

CLSCTX_RESERVED3

Deprecated.

CLSCTX_RESERVED4

Reserved for future use.

CLSCTX_NO_CODE_DOWNLOAD

Disallows the downloading of code from the Directory Service or the Internet. This flag cannot be set at the same time as CLSCTX_ENABLE_CODE_DOWNLOAD.

If the COMClassStore policy enables automatic installation, CLSCTX_NO_CODE_DOWNLOAD can be used to explicitly disallow download for an activation. If either of the following registry keys is enabled, automatic download of missing classes is enabled:

• HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\App Management
  Value Name: COMClassStore, ValueType: DWORD. 1 = enabled, 0 = disabled (default = 0)
  
• HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\App Management
  Value Name: COMClassStore, ValueType: DWORD. 1 = enabled, 0 = disabled (default = 0)
  

CLSCTX_RESERVED5

Deprecated.

CLSCTX_NO_CUSTOM_MARSHAL

Specify if you want the activation to fail if it uses custom marshalling.

CLSCTX_ENABLE_CODE_DOWNLOAD

Allows the downloading of code from the Directory Service or the Internet. This flag cannot be set at the same time as CLSCTX_NO_CODE_DOWNLOAD.

CLSCTX_NO_FAILURE_LOG

The CLSCTX_NO_FAILURE_LOG can be used to override the logging of failures in CoCreateInstanceEx. If the ActivationFailureLoggingLevel is created, the following values can determine the status of event logging:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole

Value Name: ActivationFailureLoggingLevel, ValueType: DWORD.

• 0 = Discretionary logging. Log by default, but clients can override by specifying CLSCTX_NO_FAILURE_LOG in CoCreateInstanceEx.
  
• 1 = Always log all failures no matter what the client specified.
  
• 2 = Never log any failures no matter what client specified. If the registry entry is missing, the default is 0. If you need to control customer applications, it is recommended that you set this value to 0 and write the client code to override failures. It is strongly recommended that you do not set the value to 2. If event logging is disabled, it is more difficult to diagnose problems.
  

CLSCTX_DISABLE_AAA

Disables activate-as-activator (AAA) activations for this activation only. This flag overrides the setting of the EOAC_DISABLE_AAA flag from the EOLE_AUTHENTICATION_CAPABILITIES enumeration. This flag cannot be set at the same time as CLSCTX_ENABLE_AAA. It can be used with Microsoft Windows XP and later versions.

Any activation where a server process would be launched under the caller's identity is known as an activate-as-activator (AAA) activation. Disabling AAA activations allows an application that runs under a privileged account (such as LocalSystem) to help prevent its identity from being used to launch untrusted components.

Library applications that use activation calls should always set this flag during those calls. This helps prevent the library application from being used in an escalation-of-privilege security attack. This is the only way to disable AAA activations in a library application because the EOAC_DISABLE_AAA flag from the EOLE_AUTHENTICATION_CAPABILITIES enumeration is applied only to the server process and not to the library application.

CLSCTX_ENABLE_AAA

Enables activate-as-activator (AAA) activations for this activation only. This flag overrides the setting of the EOAC_DISABLE_AAA flag from the EOLE_AUTHENTICATION_CAPABILITIES enumeration. This flag cannot be set at the same time as CLSCTX_DISABLE_AAA. It can be used with Windows XP and later versions.

Any activation where a server process would be launched under the caller's identity is known as an activate-as-activator (AAA) activation. Enabling this flag allows an application to transfer its identity to an activated component.

CLSCTX_FROM_DEFAULT_CONTEXT

Begin this activation from the default context of the current apartment.

CLSCTX_ACTIVATE_32_BIT_SERVER

Activate or connect to a 32-bit version of the server; fail if one is not registered.

CLSCTX_ACTIVATE_64_BIT_SERVER

Activate or connect to a 64 bit version of the server; fail if one is not registered.

Values from the CLSCTX enumeration are used in activation calls (CoCreateInstance, CoCreateInstanceEx, CoGetClassObject, and so on) to indicate the preferred execution contexts—in-process, local, or remote—in which an object is to be run. They are also used in calls to CoRegisterClassObject to indicate the set of execution contexts in which a class object is to be made available for requests to construct instances (IClassFactory::CreateInstance).

To indicate that more than one context is acceptable, you can combine multiple values with Boolean ORs. The contexts are tried in the order in which they are listed.

The following table shows how other functions and methods that call CoGetClassObject use the CLSCTX values.

The CLSCTX_REMOTE_SERVER value is added to the CLSCTX enumeration for distributed COM. The CLSCTX_SERVER and CLSCTX_ALL constants are further updated to include the CLSCTX_REMOTE_SERVER value.

Given a set of CLSCTX flags, dwClsCtx, the execution context to be used depends on the availability of registered class codes and other parameters according to the following algorithm.

The first part of the processing determines whether CLSCTX_REMOTE SERVER should be specified as follows.

1. If the call specifies one of the following:
   
   1. An explicit COSERVERINFO structure indicating a machine different from the current machine.
      
   2. No explicit COSERVERINFO structure specified but the specified class is registered with either the RemoteServerName or the ActivateAtStorage named-value.
      
   In either case, CLSCTX_REMOTE_SERVER is implied and is added to dwClsCtx. The second case allows applications written prior to the release of distributed COM to be the configuration of classes for remote activation to be used by client applications available prior to DCOM and the CLSCTX_REMOTE_SERVER flag. The cases in which there would be no explicit COSERVERINFO structure are as follows:
   
   1. The value is specified as NULL.
      
   2. It is not one of the function parameters, as would be the case in calls to CoCreateInstance or CoGetClassObject in existing applications.
      
2. If the explicit COSERVERINFO parameter indicates the current computer, CLSCTX_REMOTE_SERVER is removed (if present) from dwClsCtx.
   

The rest of the processing proceeds by looking at the value(s) of dwClsCtx in the following sequence:

1. If dwClsCtx includes CLSCTX_REMOTE_SERVER and no COSERVERINFO parameter is specified and if the activation request indicates a persistent state from which to initialize the object (with CoGetInstanceFromFile, CoGetInstanceFromIStorage, or, for a file moniker, in a call to IMoniker::BindToObject) and the class has an ActivateAtStorage subkey or no class registry information whatsoever, the request to activate and initialize is forwarded to the computer where the persistent state resides. (Refer to the remote activation functions listed in the See Also section for details.)
   
2. If dwClsCtx includes CLSCTX_INPROC_SERVER, the class code in the DLL found under the class's InprocServer32 key is used if this key exists. The class code will run within the same process as the caller.
   
3. If dwClsCtx includes CLSCTX_INPROC_HANDLER, the class code in the DLL found under the class's InprocHandler32 key is used if this key exists. The class code will run within the same process as the caller.
   
4. If dwClsCtx includes CLSCTX_LOCAL_SERVER, the class code in the Win32 service found under the class's LocalService key is used if this key exists. If no Win32 service is specified but an EXE is specified under that same key, the class code associated with that EXE is used. The class code (in either case) will be run in a separate service process on the same machine as the caller.
   
5. If dwClsCtx is set to CLSCTX_REMOTE_SERVER and an additional COSERVERINFO parameter to the function specifies a particular remote computer, a request to activate is forwarded to this remote computer with dwClsCtx modified to be CLSCTX_LOCAL_SERVER. The class code will run in its own process on this specific computer, which must be different from that of the caller.
   
6. Finally, if dwClsCtx includes CLSCTX_REMOTE_SERVER and no COSERVERINFO parameter is specified and if a computer name is given under the class's RemoteServerName named-value, the request to activate is forwarded to this remote computer with dwClsCtx modified to be CLSCTX_LOCAL_SERVER. The class code will run in its own process on this specific computer, which must be different from that of the caller.
   

CLSCTX_ACTIVATE_32_BIT_SERVER and CLSCTX_ACTIVATE_64_BIT_SERVER

For an explanation of the requirement values, see Requirements (COM).

Windows NT/2000/XP: Requires Windows NT 3.1 or later.

Windows 95/98: Requires Windows 95 or later.

Header: Declared in wtypes.h.

Reference

Concepts