This function reads data from a handle opened by the FtpOpenFile, FtpFindFirstFile, or HttpOpenRequest function.
At a Glance
| Header file: | Wininet.h |
| Windows CE versions: | 2.0 and later |
Syntax
BOOL WINAPI InternetReadFile(IN HINTERNET hFile, IN LPVOID lpBuffer, IN DWORD dwNumberOfBytesToRead, OUT LPDWORD lpdwNumberOfBytesRead);
Parameters
hFile
Valid handle returned from a previous call to InternetOpenUrl, FtpOpenFile, r HttpOpenRequest.
lpBuffer
Long pointer to a buffer that receives the data read.
dwNumberOfBytesToRead
Specifies the number of bytes to read.
lpNumberOfBytesRead
Long pointer to a variable that receives the number of bytes read. InternetReadFile sets this value to zero before doing any work or error checking.
Return Values
TRUE indicates success. FALSE indicates failure. To get extended error information, call GetLastError. An application can also use InternetGetLastResponseInfo when necessary.
Windows CE Remarks
Windows CE supports valid internet handles returned by HTTPOpenRequest, FtpOpenFile, and FtpFindFirstFile.
The InternetReadFile function can be completed in either synchronous or asynchronous mode.
Remarks
If the return value is TRUE and the number of bytes read is zero, the transfer has been completed and there are no more bytes to read on the handle. This is analogous to reaching EOF in a local file. Call InternetCloseHandle to free the connection to the server.
The buffer pointed to by lpBuffer is not always filled by calls to InternetReadFile (sufficient data might not have arrived from the server). When reading HTML data, for the first read posted, the buffer must be large enough to hold the HTML headers. When reading HTML-encoded directory entries, the buffer must be large enough to hold at least one complete entry.
When the item being read is also being cached by a Win32 Internet function, the application must ensure that a read is made for end-of-file so the cache file is committed correctly.
This function always fulfills the user's request. If more data is requested than is available, the function waits until enough data to complete the request is available. The only time that less data is returned than requested is when the end of the file has been reached.
This function can also be used to retrieve FTP directory listings as an HTML document on a handle opened by InternetOpenUrl. The INTERNET_FLAG_RAW_DATA value must not have been specified in the call to InternetOpenUrl.
If the HINTERNET handle stored in hFile was created by HttpOpenRequest and sent by HttpSendRequestEx, a call to HttpEndRequest must be made on the handle before InternetReadFile is used.