InternetQueryDataAvailable Function

---

Queries the server to determine the amount of data available.

Syntax

BOOL InternetQueryDataAvailable( 
    IN HINTERNET hFile,
    OUT LPDWORD lpdwNumberOfBytesAvailable,
    IN DWORD dwFlags,
    IN DWORD dwContext
);

Parameters

hFile

Valid HINTERNET handle, as returned by InternetOpenUrl, FtpOpenFile, GopherOpenFile, or HttpOpenRequest.

lpdwNumberOfBytesAvailable

Optional. Address of an unsigned long integer variable that receives the number of available bytes.

dwFlags

Reserved. Must be set to zero.

dwContext

Reserved. Must be set to zero.

Return Value

Returns TRUE if the function succeeds, or FALSE otherwise. To get extended error information, call GetLastError. If the function finds no matching files, GetLastError returns ERROR_NO_MORE_FILES.

Remarks

This function returns the number of bytes of data that are available to be read immediately by a subsequent call to InternetReadFile. If there is currently no data available and the end of the file has not been reached, the request waits until data becomes available. The amount of data remaining will not be recalculated until all available data indicated by the call to InternetQueryDataAvailable is read.

For HINTERNET handles created by HttpOpenRequest and sent by HttpSendRequestEx, a call to HttpEndRequest must be made on the handle before InternetQueryDataAvailable can be used.

Function Information

Windows NT	Use version 4.0. Implemented only as an ANSI function.
Windows	Use Windows 95 and later. Implemented only as an ANSI function.
Header	Wininet.h
Import library	Wininet.lib
Minimum availability	Internet Explorer 3.0

Windows CE

Windows CE	Use version 2.12 and later
Minimum availability	Internet Explorer 4.0

See Also

Microsoft Win32 Internet Functions Overview, Common Functions, Microsoft Win32 Internet Functions Reference, General Win32 Internet Functions