Volume Number: 15 (1999)
Issue Number: 5
Column Tag: Tips & Tidbits

May 99 Tips

by Jeff Clites <online@mactech.com>

The NSDocument and NSDocumentController classes in the Yellow Box AppKit make it trivial to create multi-document applications on Mac OS X Server. However the default behavior is to always open a new file on launching the app. Fortunately there is an easy solution to prevent this behavior. In your NSApplication object's delegate, add the following method:

-   (BOOL) applicationShouldOpenUntitledFile: 
                            (NSApplication *)sender
{
   return NO;
}

Your application will no longer automatically open a blank document on launch! A better solution might be to take that setting from the defaults database, allowing you to control this behavior via a preference panel:

-   (BOOL) applicationShouldOpenUntitledFile: 
                                          (NSApplication *)sender
{
   return [[NSUserDefaults standardUserDefaults] 
               boolForKey:@"applicationShouldOpenUntitledFile"];
}

If the default applicationShouldOpenUntitledFile is set to YES, then a new empty document will be created.

Scott Anguish
<sanguish@digifix.com>

It's easy to forget that even when you think you are just writing a simple console application, you are really writing an honest-to-goodness Macintosh application with a GUI. With CodeWarrior you are actually using the SIOUX library, which does all of the work of tricking you into thinking you are writing in pure C or C++. Actually, SIOUX allows you to customize many things, such as window title, font and font size, and whether it should auto-save its contents upon quitting. Most usefully, it lets you use Mac Toolbox calls and post events to your application's event queue. Here are Mac implementations as few common console routines to demonstrate the possibilities, courtesy of Metrowerks' MWRon <MWRon@metrowerks.com>. SIOUX is fully documented in the MSL C Reference on the CodeWarrior Reference CD.

/*MyConsole.h */
#include <stdio.h>
#include <SIOUX.h>
#include <Events.h>
#include <stdlib.h>
#include <ctype.h>

/* MyConsole.c */
void clrscr(void);
int kbhit(void);
int getch(void);

 
void clrscr(void)
{
   EventRecord rEvent;
 
   rEvent.what = keyDown;
   rEvent.when = TickCount( );
   rEvent.message = 'a';
   rEvent.modifiers = cmdKey; 
   SIOUXHandleOneEvent( &rEvent );

   rEvent.what = keyDown;
   rEvent.when = TickCount( );
   rEvent.message = 0x7F;   
   rEvent.modifiers = 0;
   SIOUXHandleOneEvent( &rEvent );
}

int kbhit(void)
{
   EventRecord event; 
   return EventAvail(keyDownMask,&event); 
}

int getch(void)
{
   int c;
   EventRecord event;
   fflush(stdout);
   
   // Allow SIOUX response for the mouse, drag, zoom, or resize.
   while(!GetNextEvent(keyDownMask,&event))
   {
      if(GetNextEvent(mDownMask|mUpMask,&event))
         SIOUXHandleOneEvent(&event);
   }

   c = event.message&charCodeMask;
   if(c=='.' && (event.modifiers&cmdKey))exit(1);
 
   return c;
}