IHttpContext::GetServerVarChanges Method

Retrieves the changes to the server variables for the current context.

Syntax

virtual HRESULT GetServerVarChanges(  
   IN DWORD dwOldChangeNumber,  
   OUT DWORD* pdwNewChangeNumber,  
   IN OUT DWORD* pdwVariableSnapShot,  
   IN OUT PCSTR** ppVariableNameSnapShot,  
   IN OUT PCWSTR** ppVariableValueSnapShot,  
   OUT DWORD* pdwDiffedVariables,  
   OUT DWORD** ppDiffedVariableIndices  
) = 0;  

Parameters

dwOldChangeNumber
[IN] A DWORD that contains the old change number.

pdwNewChangeNumber
[OUT] A pointer to a DWORD that contains the new change number.

pdwVariableSnapShot
[IN][OUT] A pointer to a DWORD that contains the number of server variables in the snapshot.

ppVariableNameSnapShot
[IN][OUT] A pointer to the address of a string array that contains the names of the server variables that were changed in the snapshot.

ppVariableValueSnapShot
[IN][OUT] A pointer to the address of a string array that contains the values of the server variables that were changed in the snapshot.

pdwDiffedVariables
[OUT] A pointer to a DWORD that contains the number of server variables that have changed.

ppDiffedVariableIndices
[OUT] A pointer to the address of an array of DWORD values, terminated by a –1 value, that contains the indices of server variables that have changed.

Return Value

An HRESULT. Possible values include, but are not limited to, those in the following table.

Value	Description
S_OK	Indicates that the operation was successful.

Remarks

IIS uses the GetServerVarChanges method to test for changes to the HTTP server variables since the last time the server variables were examined.

Note

IIS uses the GetServerVarChanges method to internally synchronize the server variables between calls to native and managed code. Developers should not use the GetServerVarChanges method when creating their HTTP modules.

Requirements

Type	Description
Client	- IIS 7.0 on Windows Vista - IIS 7.5 on Windows 7 - IIS 8.0 on Windows 8 - IIS 10.0 on Windows 10
Server	- IIS 7.0 on Windows Server 2008 - IIS 7.5 on Windows Server 2008 R2 - IIS 8.0 on Windows Server 2012 - IIS 8.5 on Windows Server 2012 R2 - IIS 10.0 on Windows Server 2016
Product	- IIS 7.0, IIS 7.5, IIS 8.0, IIS 8.5, IIS 10.0 - IIS Express 7.5, IIS Express 8.0, IIS Express 10.0
Header	Httpserv.h

See Also

IHttpContext Interface
IHttpContext::GetServerVariable Method