RetrieveUrlCacheEntryStream Function

---

Provides the most efficient and implementation-independent way of accessing the cache data.

Syntax

HANDLE RetrieveUrlCacheEntryStream(
    IN LPCTSTR lpszUrlName,
    OUT LPINTERNET_CACHE_ENTRY_INFO lpCacheEntryInfo, 
    IN OUT LPDWORD lpdwCacheEntryInfoBufferSize,
    IN BOOL fRandomRead,
    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 source name of the cache entry. This must be a unique name. The name string should not contain any escape characters.

lpCacheEntryInfo

Address of an INTERNET_CACHE_ENTRY_INFO structure that receives information about the cache entry.

lpdwCacheEntryInfoBufferSize

Address of an unsigned long integer variable that specifies the size of the lpCacheEntryInfo buffer, in TCHARs. When the function returns, the variable receives the number of TCHARs copied to the buffer, or the required size of the buffer, in bytes.

fRandomRead

Boolean value that indicates whether the stream is open for random access. Set the flag to TRUE to open the stream for random access.

dwReserved

Reserved. Must be set to zero.

Return Value

Returns a valid handle for use in the ReadUrlCacheEntryStream and UnlockUrlCacheEntryStream functions if successful, or NULL 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 lpCacheEntryInfo as specified by lpdwCacheEntryInfoBufferSize is not sufficient to contain all the information. The value returned in lpdwCacheEntryInfoBufferSize indicates the buffer size necessary to contain all the information.

Remarks

RetrieveUrlCacheEntryStream 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 is passed, the function returns ERROR_FILE_NOT_FOUND even if http://example.com/example.htm is in the cache.

Cache clients that do not need URL data in the form of a file should use this function to access the data for a particular URL.

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)

See Also

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