AllocMemoryPerRequest Callback Function

Article
08/13/2010

The AllocMemoryPerRequest callback function is used to allocate memory (from the process heap to a buffer) per request. Any memory allocated by using this function will automatically be freed by the Forefront TMG Web proxy at the end of the request (after the SF_NOTIFY_END_OF_REQUEST notification) even if the session continues. For more information about the types of event notifications that are sent to Web filters, see Event Notifications.

If the memory cannot be allocated, this function returns NULL.

The AllocMemoryPerRequest callback function is declared as:

Syntax

VOID * WINAPI * AllocMemoryPerRequest(
  __in  struct _HTTP_FILTER_CONTEXT* pfc,
  __in  DWORD cbSize,
  __in  DWORD dwReserved
);

Parameters

pfc
Pointer to the HTTP_FILTER_CONTEXT data structure that is associated with the current, active HTTP session. Pass the filter context in this parameter.
cbSize
Indicates the size of the buffer to be allocated, in bytes.
dwReserved
Reserved for use by the server.

Return Value

This callback function does not return a value.

Remarks

The AllocMemoryPerRequest function is called through a pointer that is a member of the WPX_FILTER_CONTEXT structure. To get a pointer to the WPX_FILTER_CONTEXT structure for calling the AllocMemoryPerRequest function, use the TO_WPX_FILTER_CONTEXT macro as follows:

WPX_FILTER_CONTEXT* pwfc = TO_WPX_FILTER_CONTEXT(pfc);
if (pwfc != NULL) {
...
}

Requirements

Server	Requires Windows Server 2008 R2 or Windows Server 2008 x64 Edition with SP2.
Version	Requires Forefront Threat Management Gateway (TMG) 2010.
Header	Declared in Wpxhttpfilt.h.
DLL	Requires W3Filter.dll.

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