Export (0) Print
Expand All
Expand Minimize

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_PTR dwContext
);

Parameters

hFile [in]

Handle returned by the InternetOpenUrl, FtpOpenFile, GopherOpenFile, or HttpOpenRequest function.

lpdwNumberOfBytesAvailable [out]

Pointer to a variable that receives the number of available bytes. May be NULL.

dwFlags [in]

This parameter is reserved and must be 0.

dwContext [in]

This parameter is reserved and must be 0.

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.

Like all other aspects of the WinINet API, this function cannot be safely called from within DllMain or the constructors and destructors of global objects.

Note  WinINet does not support server implementations. In addition, it should not be used from a service. For server implementations or services use Microsoft Windows HTTP Services (WinHTTP).

Requirements

Minimum supported client

Windows 2000 Professional

Minimum supported server

Windows 2000 Server

Header

Wininet.h

Library

Wininet.lib

DLL

Wininet.dll

See also

Common Functions
WinINet Functions

 

 

Show:
© 2014 Microsoft