CoCreateInstanceFromApp function (combaseapi.h)

Article
10/13/2021

Creates an instance of a specific class on a specific computer from within an app container.

Syntax

HRESULT CoCreateInstanceFromApp(
  [in]           REFCLSID Clsid,
  [in, optional] IUnknown *punkOuter,
  [in]           DWORD    dwClsCtx,
  [in, optional] PVOID    reserved,
  [in]           DWORD    dwCount,
  [in, out]      MULTI_QI *pResults
);

Parameters

[in] Clsid

The CLSID of the object to be created.

[in, optional] punkOuter

If this parameter non-NULL, indicates the instance is being created as part of an aggregate, and punkOuter is to be used as the new instance's controlling IUnknown. Aggregation is currently not supported cross-process or cross-computer. When instantiating an object out of process, CLASS_E_NOAGGREGATION will be returned if punkOuter is non-NULL.

[in] dwClsCtx

A value from the CLSCTX enumeration.

[in, optional] reserved

Reserved for future use.

[in] dwCount

The number of structures in pResults. This value must be greater than 0.

[in, out] pResults

An array of MULTI_QI structures. Each structure has three members: the identifier for a requested interface (pIID), the location to return the interface pointer (pItf) and the return value of the call to QueryInterface (hr).

Return value

This function can return the standard return value E_INVALIDARG, as well as the following values.

Return code	Description
S_OK	Indicates success.
REGDB_E_CLASSNOTREG	A specified class is not registered in the registration database, or the class is not supported in the app container. Also can indicate that the type of server you requested in the CLSCTX enumeration is not registered or the values for the server types in the registry are corrupt.
CLASS_E_NOAGGREGATION	This class cannot be created as part of an aggregate.
CO_S_NOTALLINTERFACES	At least one, but not all of the interfaces requested in the pResults array were successfully retrieved. The hr member of each of the MULTI_QI structures in pResults indicates with S_OK or E_NOINTERFACE whether the specific interface was returned.
E_NOINTERFACE	None of the interfaces requested in the pResults array were successfully retrieved.

Remarks

The CoCreateInstanceFromApp function is the same as the CoCreateInstanceEx function, with the following differences.

The CoCreateInstanceFromApp function reads class registrations only from application contexts, and from the HKLM\SOFTWARE\Classes\CLSID registry hive.
Only built-in classes that are supported in the app container are supplied. Attempts to activate unsupported classes, including all classes installed by 3rd-party code as well as many Windows classes, result in error code REGDB_E_CLASSNOTREG.
The CoCreateInstanceFromApp function is available to Windows Store apps. Desktop applications can call this function, but they have the same restrictions as Windows Store apps.

Requirements

Requirement	Value
Minimum supported client	Windows 8 [desktop apps \| UWP apps]
Minimum supported server	Windows Server 2012 [desktop apps \| UWP apps]
Target Platform	Windows
Header	combaseapi.h
Library	Combase.lib
DLL	Combase.dll