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ihttpfileinfo-getfilehandle-method.md

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title IHttpFileInfo::GetFileHandle Method
description Describes the IHttpFileInfo::GetFileHandle method and details its syntax, parameters, return value, remarks, and requirements.
ms.date 10/07/2016
ms.assetid ff010463-a9a9-4e7f-5fcd-367e09aeb1cf

IHttpFileInfo::GetFileHandle Method

Returns the file handle for the corresponding file.

Syntax

virtual HANDLE GetFileHandle(  
   VOID  
) const = 0;

Parameters

This method takes no parameters.

Return Value

A valid HANDLE to the corresponding file; otherwise, INVALID_HANDLE_VALUE (defined in the Winbase.h header file).

Remarks

The returned handle must use an overlapped structure to process read requests; otherwise, the current pointer in the file handle might point to random files if multiple threads access the handle concurrently.

If the returned handle is not INVALID_HANDLE_VALUE, it will point to a valid file handle returned from a method such as the CreateFile global function.

The behavior of the GetFileHandle method is implementation specific. You should use the following information as a guideline, but it may not be correct in all scenarios:

  • Implementers that reference an Internet file return a handle to the file if opened; otherwise, implementers return INVALID_HANDLE_VALUE.

  • Implementers that reference a non-Internet file return INVALID_HANDLE_VALUE.

Notes for Implementers

IHttpFileInfo implementers are responsible for resource management with this data; therefore, IHttpFileInfo implementers must call the CloseHandle function on the HANDLE when it is no longer needed.

Notes for Callers

IHttpFileInfo implementers are responsible for resource management with this data; therefore, IHttpFileInfo clients must not call CloseHandle on the returned HANDLE when this data is no longer needed. Furthermore, clients must not change the state of the memory referenced by this HANDLE; otherwise, an access violation will be thrown or the data will become invalid.

Example

The following example demonstrates how to use the IHttpContext::GetFileInfo method to create an HTTP module that retrieves a pointer to an IHttpFileInfo interface for the current request. The example then calls the GetFileHandle method to retrieve a HANDLE to the corresponding file and displays this information to a Web client.

[!code-cppIHttpFileInfo#7]

The following text is an example of the data output from the preceding code example.

HTTP/1.1 200 OK  
content-Type:text/plain  
Server: Microsoft-IIS/7.0  
Date: Thu, 15 Dec 2005 22:22:09 GMT  
Content-Length: 348  
  
File Handle: INVALID_HANDLE_VALUE

Your module must export the RegisterModule function. You can export this function by creating a module definition (.def) file for your project, or you can compile the module by using the /EXPORT:RegisterModule switch. For more information, see Walkthrough: Creating a Request-Level HTTP Module By Using Native Code.

You can optionally compile the code by using the __stdcall (/Gz) calling convention instead of explicitly declaring the calling convention for each function.

Requirements

Type Description
Client - IIS 7.0 on [!INCLUDEwinvista]
- IIS 7.5 on Windows 7
- IIS 8.0 on Windows 8
- IIS 10.0 on Windows 10
Server - IIS 7.0 on [!INCLUDEwinsrv2008]
- 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
- [!INCLUDEiisexp75], [!INCLUDEiisexp80], [!INCLUDEiisexp100]
Header Httpserv.h

See Also

IHttpFileInfo Interface