🚀 go-pugleaf

Bob Gonder wrote:

> I have to wonder why you are asking Java/VCL/Delphi questions
> in a C++ group...

As you can see initially it was question about API problem (language
independent).

> > procedure TJvgMailSlotServer.OnTimer(Sender: TObject);
> 
> Why is this on a timer?
> There are much better ways such as threads and Read Events.

Yes, but timer is enough for beginning.

> > var
> >  MsgSize: DWORD;
> >  MsgNumber: DWORD;
> >  Read: DWORD;
> >  Buffer: Pointer;
> > begin
> >  // Determining if there's message
> >  if not GetMailSlotInfo(FHandle, nil, MsgSize, @MsgNumber, nil)
> 
> I don't know Delphi, but that looks quite wrong. I would expect
> 	GetMailSlotInfo(FHandle, nil, @MsgSize, @MsgNumber, nil)

No, code is correct. In windows.pas:

function GetMailslotInfo
 (hMailslot: THandle; lpMaxMessageSize: Pointer;
  var lpNextSize: DWORD; lpMessageCount, lpReadTimeout: Pointer):
    BOOL; stdcall;

lpNextSize (MsgSize in code) is 'var' (i.e. reference, not pointer).

> > Send works normally (always returns true).
> > Local messaging ('.\') with length up to 64K work without problems.
> > Network messaging (i.e. where name of computer was specified):
> > - up to 425 bytes in any case
> > - up to 1365 bytes after installation of NetBEUI.
> 
> In other words, One Packet.

Yes.

> You need to prefix your message with a message size,
> and have the server keep reading until it gets all of the message.
> Then have the sender break up the message into packet size.

No any packet at all if L>425 (or 1365). Manual chUnk by chUnk sending
is not so good (delivery is not guaranteed).

> The data in a mailslot message can be in any form, but cannot
> be larger than 424 bytes when sent between computers.
> http://msdn2.microsoft.com/en-us/library/aa365130.aspx

Thank you for this information. Here I see this explicit limitation for
the first time; there is no such limitation in my local (outdated) MSDN.

-- 
Alex