这些函数的技术文档在Microsoft的msdn里面
先发个函数的文档给你，赚一点分数，呵呵
Initiates access to a remote file on an FTP server for reading or writing.
Syntax
HINTERNET FtpOpenFile(
IN HINTERNET hConnect,
IN LPCTSTR lpszFileName,
IN DWORD dwAccess,
IN DWORD dwFlags,
IN DWORD_PTR dwContext
);
The actual syntax of this function varies between its ANSI and Unicode
implementations.
For more information, see Win32 Internet Functions Syntax.
Parameters
hConnect :
Valid HINTERNET handle to an FTP session.
lpszFileName :
Address of a null-terminated string that contains the name of the file
to access on the remote system.
dwAccess :
Unsigned long integer value that determines how the file will be
accessed. This can be GENERIC_READ or GENERIC_WRITE, but not both.
dwFlags :
Unsigned long integer value that contains the conditions under
which the transfers occur. The application should select one
transfer type and any of the flags that indicate how the caching
of the file will be controlled. The transfer type can be one of
the following values:
1):FTP_TRANSFER_TYPE_ASCII
Transfers the file using FTP's ASCII (Type A) transfer method.
Control and formatting information is converted to local
equivalents.
2):FTP_TRANSFER_TYPE_BINARY
Transfers the file using FTP's Image (Type I) transfer method.
The file is transferred exactly as it exists. This is the
default transfer method.
3):FTP_TRANSFER_TYPE_UNKNOWN
Defaults to FTP_TRANSFER_TYPE_BINARY.
4):INTERNET_FLAG_TRANSFER_ASCII
Transfers the file as ASCII.
5):INTERNET_FLAG_TRANSFER_BINARY
Transfers the file as binary.
The following values are used to control the caching of the file. The application
can use one or more of these.
1):INTERNET_FLAG_HYPERLINK
2):INTERNET_FLAG_NEED_FILE
3):INTERNET_FLAG_RELOAD
4):INTERNET_FLAG_RESYNCHRONIZE
dwContext :
Address of an unsigned long integer value that contains the
application-defined value that associates this search with
any application data. This is only used if the application
has already called InternetSetStatusCallback to set up a
status callback function.
Return Value
Returns a handle if successful, or NULL otherwise. To retrieve a specific error
message, call GetLastError.
