"Hello world!" in MUI

Grzegorz Kraszewski

This is the window of the example MUI application. It is very simple, it contains only one static text object and no gadgets, except of window border gadgets. Note that the number of gadgets on the right side of window depends on user MUI settings. The source code of the application is very simple too and fits into 60 lines, including proper vertical spacing. It is cut in pieces in the article for better reading, here is the ready to compile version.

#include <proto/muimaster.h>
#include <proto/intuition.h>

Header files for muimaster.library and intuition.library are included. Note that these libraries will be opened and closed automatically.

Object *App, *Win;

Global pointers for the application object and the window object. While using many global variables is considered inelegant, having globals for the most important objects is handy, especially in such a small project.

Object* build_gui(void)
{
  App = MUI_NewObject(MUIC_Application,
    MUIA_Application_Author, (ULONG)"Grzegorz Kraszewski",
    MUIA_Application_Base, (ULONG)"HELLOWORLD",
    MUIA_Application_Copyright, (ULONG)"© 2010 Grzegorz Kraszewski",
    MUIA_Application_Description, (ULONG)"Hello World in MUI.",
    MUIA_Application_Title, (ULONG)"Hello World",
    MUIA_Application_Version, (ULONG)"$VER: HelloWorld 1.0 (16.11.2010)",
    MUIA_Application_Window, (ULONG)(Win = MUI_NewObject(MUIC_Window,
      MUIA_Window_Title, (ULONG)"Hello World",
      MUIA_Window_RootObject, MUI_NewObject(MUIC_Group,
        MUIA_Group_Child, MUI_NewObject(MUIC_Text,
          MUIA_Text_Contents, (ULONG)"Hello world!",
        TAG_END),
      TAG_END),
    TAG_END)),
  TAG_END);
}

The above function creates the complete object tree for HelloWorld. The master object is the Application class instance. It has a Window object. The window root is a Group object containing one Text object. The application object has 6 attributes working as descriptors used in different places in the system. They are not required for running the program, but help integrating it with the system. The meaning of these attributes is explained in the autodoc of Application class in the SDK. The rest of attributes is self-explaining.

void notifications(void)
{
  DoMethod(Win, MUIM_Notify, MUIA_Window_CloseRequest, TRUE, App, 2,
   MUIM_Application_ReturnID, MUIV_Application_ReturnID_Quit);
}

void main_loop(void)
{
  ULONG signals = 0;

  set(Win, MUIA_Window_Open, TRUE);
			 
  while (DoMethod(App, MUIM_Application_NewInput, &signals) != MUIV_Application_ReturnID_Quit)
  {
    signals = Wait(signals | SIGBREAKF_CTRL_C);
    if (signals & SIGBREAKF_CTRL_C) break;
  }

  set(Win, MUIA_Window_Open, FALSE);
}

int main(void) { if (App = build_gui()) { notifications(); main_loop(); MUI_DisposeObject(App); } return 0; }