🚀 go-pugleaf

Bob Gonder wrote:

> Show your actual code ?

It's part of JVCL's JvgMailSlot (slightly modified):

procedure TJvgMailSlotServer.Open;
begin
 <...>
// no matter what timeout I specify here (0 or MAILSLOT_WAIT_FOREVER)
  FHandle:=CreateMailSlot(PChar('\\.\mailslot\'+MailSlotName),0,0,nil);
  if FHandle=INVALID_HANDLE_VALUE then <Err...>
  FTimer.Enabled:=True;
end;

procedure TJvgMailSlotServer.OnTimer(Sender: TObject);
var
  MsgSize: DWORD;
  MsgNumber: DWORD;
  Read: DWORD;
  Buffer: Pointer;
begin
  // Determining if there's message
  if not GetMailSlotInfo(FHandle, nil, MsgSize, @MsgNumber, nil)
  then <Err...> 
  else
    if MsgSize<>MAILSLOT_NO_MESSAGE
    then begin
      FData.Size:=MsgSize; // Allocate memory
      Buffer:=FData.Memory;
      // Reading message
      if ReadFile(FHandle, Buffer^, MsgSize, Read, nil)
      then <OK...>
      else <Err...>
    end;        
end;

function TJvgMailSlotClient.Send
 (const MessageData; MessageLength: integer): Boolean;
var
  FHandle: THandle;
  Written: DWORD;
begin
  if FServerName='' then FServerName:='.\'; // the same computer
  FHandle:=CreateFile(PChar('\\'+FServerName+'\mailslot\'+
FMailSlotName), GENERIC_WRITE, FILE_SHARE_READ, nil, OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL, 0);
  Result:=FHandle<>INVALID_HANDLE_VALUE;
  if Result then
  begin
    Result:=WriteFile(FHandle, MessageData, MessageLength, Written,
nil);
    CloseHandle(FHandle);
  end;
end;

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.

Server never see network messages longer then 1365 bytes
(i.e. MsgSize=MAILSLOT_NO_MESSAGE).

MSDN says that for long messages (up to 64K) mailslots require "SMB
session". I have no idea how to check the presence of SMB session.
-- 
Alex