While developing with simpleipc i found that there's no straightforward way to identify the type of a message (see the forth paragraph of http://lazarusroad.blogspot.com/2006/12/only-one-instance.html), so i looked what i could do to improve it.
Currently, TMessageType is defined as an enum type with two possible values: mtString and mtUnknow. If you use SendMessage mtUnknow is used if SendMessageString is used mtString is used. But the message type is not being used: under windows the message type is not even passed to the server, under linux is passed but not used.
What i propose is simple: change the TMessageType to an 32bit ordinal type (longint or longword), provide ways the user to send custom message types and add a MsgType property to IPCServer. This way the user (programmer) can send messages with different purposes and easily know what to do when they arrive. Some thing like that:
with IPCServer do
begin
case MsgType of
mtString:;
mtMyType1:;
mtMyType2:;
end;
end;The patch i'm sending does:
- Change TMessageType to longint
- Define mtString and mtUnknow as constants
- Add overloaded methods SendMessage and SendMessageString with an extra parameter (MsgType)
- Added MsgType property to TSimpleIPCServer
- Changed some capitalizations
win32
- MsgType is passed through an unused CopyDataStruct field
unix:
- No changes at all, just fixed a bug (mtString was used always)
Notice that there's no memory or resource increase since the patch uses previously unused resources.
I'm sending also a test program written in Lazarus. It was tested under win32 and linux (ubuntu 10.06)
Luiz