Windows CE 3.0

This function queries the amount of data available.

BOOL WINAPI InternetQueryDataAvailable(
LPDWORD lpdwNumberOfBytesAvailable, 
DWORD dwFlags, 
DWORD dwContext);


Valid Internet file handle, as returned by InternetOpenUrl, FtpOpenFile, or HttpOpenRequest.
Optional. Long pointer to a variable that receives the number of available bytes.
Reserved; set to zero.
Reserved; set to zero.

Return Values

TRUE indicates success. FALSE indicates failure. To get extended error information, call GetLastError. If the function finds no matching files, GetLastError returns ERROR_NO_MORE_FILES.

Windows CE Remarks

Windows CE stipulates that the hFile parameter must be a valid Internet file handle returned by the FtpOpenFile, FtpFindFirstFile, or HttpOpenRequest function.

The InternetQueryDataAvailable function can be completed in either synchronous or asynchronous mode.


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.


Runs on Versions Defined in Include Link to
Windows CE OS 2.0 and later Wininet.h   Wininet.lib
Note   This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

See Also

HINTERNET, FtpFindFirstFile, FtpOpenFile, GetLastError, HttpEndRequest, HttpOpenRequest, HttpSendRequestEx, InternetOpenUrl, InternetQueryDataAvailable, InternetReadFile

 Last updated on Tuesday, July 13, 2004

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