MSDN Library


Downloads data into the Internet cache and returns the file name of the cache location for retrieving the bits.


HRESULT URLDownloadToCacheFile(
  LPUNKNOWN lpUnkcaller,
  LPTSTR szFileName,
  DWORD dwBufLength,
  DWORD dwReserved,
  IBindStatusCallback * pBSC


Address of the controlling IUnknown interface of the calling ActiveX® component (if the caller is an ActiveX component). If the caller is not an ActiveX component, this value can be set to NULL. Otherwise, the caller is a Component Object Model (COM) object that is contained in another component (such as an ActiveX control within the context of an HTML page). This parameter represents the outermost IUnknown of the calling component. The function attempts the download within the context of the ActiveX client framework and allows the caller's container to receive callbacks on the progress of the download.
Address of a string value that contains the URL to be downloaded. This cannot be set to NULL.
Address of a string value that contains the name of the downloaded file. This cannot be set to NULL.
Unsigned long integer value that contains the size of the szFileName buffer in bytes.
Reserved. Must be set to zero.
Address of the caller's IBindStatusCallback interface. URLDownloadToCacheFile calls this interface's IBindStatusCallback::OnProgress method on a connection activity, including the arrival of data. IBindStatusCallback::OnDataAvailable is never called. Implementing IBindStatusCallback::OnProgress allows a caller to implement a user interface or other progress monitoring functionality. It also allows the download operation to be canceled by returning E_ABORT from the IBindStatusCallback::OnProgress call. This can be set to NULL.

Return Values

Returns one of the following values:

The operation failed.
The buffer length is invalid or there was insufficient memory to complete the operation.
The operation succeeded.


The client can choose to be notified of progress through a notification callback.

This function always returns a file name if the download operation succeeds. If the given URL is a "file:" URL, URLDownloadToCacheFile directly returns the file name for the "file:" URL rather than making a copy to the cache. If the given URL is an Internet URL ("http:", "ftp:"), URLDownloadToCacheFile downloads this file and returns the local file name of the cached copy. Using this function ensures that a file name is returned without unnecessary copying of data.


Smartphone: Windows Mobile 2002 and later
OS Versions: Windows CE 3.0 and later
Header: urlmon.h
Library: urlmon.lib

Last updated on Friday, April 22, 2005

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