# LockClrVersion Function

Allows the host to determine which version of the common language runtime (CLR) will be used within the process before explicitly initializing the CLR.

This function has been deprecated in the .NET Framework 4.

## Syntax

HRESULT LockClrVersion (
[in] FLockClrVersionCallback   hostCallback,
[in] FLockClrVersionCallback  *pBeginHostSetup,
[in] FLockClrVersionCallback  *pEndHostSetup
);


## Parameters

hostCallback
[in] The function to be called by the CLR upon initialization.

pBeginHostSetup
[in] The function to be called by the host to inform the CLR that initialization is starting.

pEndHostSetup
[in] The function to be called by the host to inform the CLR that initialization is complete.

## Return Value

This method returns standard COM error codes, as defined in WinError.h, in addition to the following values.

Return code Description
S_OK The method completed successfully.
E_INVALIDARG One or more of the arguments is null.

## Remarks

The host calls LockClrVersion before initializing the CLR. LockClrVersion takes three parameters, all of which are callbacks of type FLockClrVersionCallback. This type is defined as follows.

typedef HRESULT ( __stdcall *FLockClrVersionCallback ) ();


The following steps occur upon initialization of the runtime:

1. The host calls CorBindToRuntimeEx or one of the other runtime initialization functions. Alternatively, the host could initialize the runtime using COM object activation.

2. The runtime calls the function specified by the hostCallback parameter.

3. The function specified by hostCallback then makes the following sequence of calls:

• The function specified by the pBeginHostSetup parameter.

• CorBindToRuntimeEx (or another runtime initialization function).

• The function specified by the pEndHostSetup parameter.

All the calls from pBeginHostSetup to pEndHostSetup must occur on a single thread or fiber, with the same logical stack. This thread can be different from the thread upon which hostCallback is called.

## Requirements

Platforms: See System Requirements.

Header: MSCorEE.h

Library: MSCorEE.dll

.NET Framework Versions: Available since 2.0