RetrieveUrlCacheEntryFile Function

---

Locks the cache entry file associated with the specified URL.

Syntax

BOOL RetrieveUrlCacheEntryFile(
    IN LPCTSTR lpszUrlName,
    OUT LPINTERNET_CACHE_ENTRY_INFO lpCacheEntryInfo, 
    IN OUT LPDWORD lpdwCacheEntryInfoBufferSize,
    IN DWORD dwReserved
);

The actual syntax of this function varies between its ANSI and Unicode implementations. For more information, see Win32 Internet Functions Syntax.

Parameters

lpszUrlName

Address of a string that contains the URL of the resource associated with the cache entry. This must be a unique name. The name string should not contain any escape characters.

lpCacheEntryInfo

Address of a cache entry information buffer. If the buffer is not sufficient, this function returns ERROR_INSUFFICIENT_BUFFER and sets lpdwCacheEntryInfoBufferSize to the number of bytes required.

lpdwCacheEntryInfoBufferSize

Address of an unsigned long integer variable that specifies the size of the lpCacheEntryInfo buffer, in TCHARs. When the function returns, the variable contains the size, in TCHARs, of the actual buffer used or the number of bytes required to retrieve the cache entry file. The caller should check the return value in this parameter. If the return size is less than or equal to the size passed in, all the relevant data has been returned.

dwReserved

Reserved. Must be set to zero.

Return Value

Returns TRUE if successful, or FALSE otherwise. To get extended error information, call GetLastError. Possible error values include:

ERROR_FILE_NOT_FOUND	The cache entry specified by the source name is not found in the cache storage.
ERROR_INSUFFICIENT_BUFFER	The size of the lpCacheEntryInfo buffer as specified by lpdwCacheEntryInfoBufferSize is not sufficient to contain all the information. The value returned in lpdwCacheEntryInfoBufferSize indicates the buffer size necessary to get all the information.

Remarks

RetrieveUrlCacheEntryFile does not do any URL parsing, so a URL containing an anchor (#) will not be found in the cache, even if the resource is cached. For example, if the URL http://example.com/example.htm#sample was passed, the function would return ERROR_FILE_NOT_FOUND even if http://example.com/example.htm is in the cache.

The file is locked for the caller when it is retrieved; the caller should unlock the file after it has been used up. The cache manager automatically unlocks the files after a certain interval. While the file is locked, the cache manager will not remove the file from the cache. It is important to note that this function can be efficient or expensive, depending on the internal implementation of the cache. For instance, if the URL data is stored in a packed file that contains data for other URLs, the cache will make a copy of the data to a file in a temporary directory maintained by the cache. The cache will eventually delete the copy. It is recommended that this function be used only in situations where a file name is needed to launch an application. RetrieveUrlCacheEntryStream and associated stream functions should be used in most cases.

Function Information

Windows NT	Use version 4.0. Implemented as ANSI and Unicode functions.
Windows	Use Windows 95 and later. Implemented as ANSI and Unicode functions.
Header	Wininet.h
Import library	Wininet.lib
Minimum availability	Internet Explorer 3.0 (ANSI only), 5 (ANSI and Unicode)

Windows CE

Windows CE	Use version 2.12 and later. Implemented as ANSI and Unicode functions.
Minimum availability	Internet Explorer 4.0

See Also

Microsoft Win32 Internet Functions Overview, Caching, Microsoft Win32 Internet Functions Reference, Persistent URL Cache Functions