Hi Thiago: Thank you for your explain so much of dbus tech detail. I am glad to explain what I am doing. It is a "open with" function of applications manager in smart phone. when user click a *.mp3 file in file manager, a open with file message will be sent to app manager, app manager will find certain media player to launch it to open the mp3 file. before i implement it by Qt QCopchannel, store the message in /tmp/pid-message RAM file by  "data >> QByteArray". when media player is started, it will read the /tmp/pid-message file and send out a signal in MediaApplication.cpp  class. Now, I implement it by Gtk and dbus. Also I want to do it by write and read /tmp/pid-message, but i don not know how to store into and read from a dbus message pid-message. I know some test code can write and read dbus message into a file, but i can not find the source code. It is easy to implement by "command lines",  something like  "MediaPlayer  /a/mp3/file.mp3" but we want to make it a more general facility , something like  open_file_with_app_and_save_setting_and_tell_user  (const std::string  &file,  const  std::string  &app,  bool  save, const std::string &user_message); it is a auto message which is sent to app manager by file manager, app manager will check if the media player is live, if live, then send the message, if not live, should start the media player first, and after the player is ready to receive the message, send message then. <div>On 1/25/07, Thiago Macieira <<a href="mailto:thiago@kde.org" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)"> thiago@kde.org</a>> wrote:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> anlong sun wrote: >And we think queued messages function is very useful and valueble. I don't. I think it's an abuse of the current system. In any event, if this is implemented at all, it needs to be added as a new feature, under a new flag, for D-Bus 1.2.x. Common messages today cannot have any extra timeout.</blockquote><div> Great, I am waitting for 1.2.x!  </div> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">>Because it is more simple for developer : do not need write the .service >file I think that's a cost that's worth it. The alternative is to wait for D-Bus 1.2.0. >Also this function will not make bad the performance of dbus deamon, If you have not written the code and tested it, do not make this claim. </blockquote><div> Yes, i have not written and tested the source code:) It is difficult to predict the performance when add a new feature. Marketing and Salse guys tends to say like that, I am a engineer:)  </div> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">>for example after a certain time (30 seconds), deamon will delete the > queued messages. > >Is it difficult to implement it? Cannot say. Maybe not, since every message already has a timer -- the timeout one.</blockquote><div> It will be a great feature, at least for us:)  </div> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">-- Thiago Macieira - thiago (AT) <a href="http://macieira.info" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)"> macieira.info </a> - thiago (AT) <a href="http://kde.org" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">kde.org</a>   PGP/GPG: 0x6EF45358; fingerprint:   E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358 </blockquote></div>