Tips & Tidbits

By Dave Mark, Neil Ticktin, Editor

Hidden deep inside System 7, there are a set of 3 Toolbox traps so secret, they aren’t even included in the THINK C interfaces. The three routines are SetDialogDefaultItem(), SetDialogCancelItem(), and SetDialogTracksCursor(). To access these three routines, include these three declarations at the top of your source code file:

/* 1 */

pascal OSErr SetDialogDefaultItem( DialogPtr theDialog, short newItem 
) = { 0x303C, 0x0304, 0xAA68 };    
pascal OSErr SetDialogCancelItem( DialogPtr theDialog, short newItem 
) = { 0x303C, 0x0305, 0xAA68 };
pascal OSErr SetDialogTracksCursor( DialogPtr theDialog, Boolean tracks 
) = { 0x303C, 0x0306, 0xAA68 };

SetDialogDefaultItem() allows you to specify a dialog’s default item. More importantly, it will ensure that the thick, rounded rectangle is drawn around the default item, something you normally do yourself.

SetDialogCancelItem() ties an item to the key sequence command-period. Typically, you’ll want to tie this functionality to the Cancel button.

Finally, SetDialogTracksCursor() tells the Dialog Manager to use the i-beam cursor when the cursor enters an editable text field.

Forcing a Quit

Under System 7, if you hold down the command and option keys and then press the escape key, you can force an application to quit. This key sequence brings up a dialog box, asking if you’d like to “force a quit”. Be careful with this, as you’ll lose any unsaved changes. This technique works, no matter what application you are in.

Now here’s the cool part. In the Finder, hold down the command and option keys and press the escape key. When the dialog box appears, click the Force Quit button, but continue to hold the command and option keys down. The Finder will restart, asking you if you’d like to rebuild the desktop database on all available volumes. Pretty slick, huh?

Custom Finder Icons

You can create custom Finder icons for any file under System 7. Go into the Scrapbook and copy your favorite PICT image into the clipboard. Back in the Finder, click on any icon, then select Get Info from the File menu. When the Get Info window appears, click on the icon in the upper left corner of the window. A 1 pixel border should appear around the icon. Select Paste from the Edit menu. You’ve just added a custom icon to the file. You can read about custom icons in Inside Macintosh, Volume VI on page 9-28.