TweetFollow Us on Twitter

May 95 Tips
Volume Number:11
Issue Number:5
Column Tag:Tips & Tidbits

Tips & Tidbits

By Scott T Boyd, Editor

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

TIP OF THE MONTH

Flush Out Your Bugs

Before releasing an application to your testers, load these three extensions: EBBE (Even Better Bus Error), DisposeResource, and DoubleTrouble. They check for NIL dereferences, improperly-disposed resources, and multiply-disposed memory manager blocks. [You can find these extensions in many places, including our ftp and other online sites - Ed stb] Run your application. You may be surpised at what you find.

Using these debugging tools, I caught a bug in an application based on the 1/18/95 release of Sprocket. This bug was fixed in the 1/25/95 Sprocket release, and does not exist in the 12/94 release. I’m using this code both as an example and a suggested patch if you are using the 1/18 version of Sprocket.

TSplashWindow::~TSplashWindow()
        {
        if (fSplashPicture)
                DisposeHandle((Handle) fSplashPicture);  // Oops!
        this->Close();
        }

TWindow::Close(void)
        {
        WindowPtr       newFrontWindow = nil;
        if (FrontNonFloatingWindow() == fWindow)
          newFrontWindow = (WindowPtr)((WindowPeek)fWindow)->nextWindow;
        this->Activate(false);
        DisposeWindow(fWindow);
        if (newFrontWindow)
           HiliteAndActivateWindow(newFrontWindow,true);
        return true;
        }

When I ran the executable, I dropped into my low level debugger, and looked at the stack. Return addresses on the stack from the MacsBug stack crawl sc7:

  Stack Addr  Frame Addr   Caller
   01C6ECD0               01B6D6D2 'CODE 0001 2690 Sprocket Lib'+0172
   01C6ECC8               01B6D692 'CODE 0001 2690 Sprocket Lib'+0132
   01C6ECAA    01C6ECA6   01B6E9F8 main+01F2
   01C6EC9E    01C6EC9A   01B6EF7A TSplashWindow::~TSplashWindow()+002C
   01C6EC88               01B6FA3C TWindow::Close()+0034
   01C6EC80    01C6EC7C   408578C4 _DisposeWindow+0004
   01C6EC6C               4085A846 _FrontWindow+0096
   01C6EC54               40877EB4 _KillPicture+0004
   01C6EC40               4085785C _NewWindow+010C
   01C6EC34               40877EB4 _KillPicture+0004
   01C6EC30               4085785C _NewWindow+010C

From this stack trace I saw that fSplashPicture got disposed again by DisposeWindow(fWindow); A review of the code showed the offending extra Dispose in ~TSplashWindow().

Why not leave these debugging resources on your system all the time? Well, it appears that not everyone uses these tools religiously and several other of my favorite (nameless) applications write to location Zero and trigger EBBE. I’ve sent in bug reports to the offenders, but I am still waiting for all the update releases.

Happy Bug Trails!

- Gary W. Powell
gpowell@mv.us.adobe.com

Powering Up The RTM Instruction

For you power programmers out there, here’s a little tip on taking advantage of the PowerPC architecture. Where you might have used the 68020 RTM instruction (Return from Module), you can get a lot of mileage by using the new PowerPC RTFM instruction instead. We can assure you that you will save literally hours of time.

- David Gorkan and Allan Foster

Save a Little Time

Here is a great and easy way to supercharge File Open... File Save and File Save As... operations from any application, especially if you use the Apple Menu Items to store aliases to folders: Make an alias of the Apple Menu Items folder and put it on the Desktop.

What does that get you? Well, since the Standard file Get and Put Dialogs all have a Desktop button, you can easily get to the Apple Menu Items, and hence access any aliases that are stored there. Just Click on the Desktop folder and the Apple Menu Item Alias appears as a supercharged Volume of Aliases.

But wait, there’s more! You get a real bonus from using System 7.5 because, if you put the Apple Menu Items alias onto the desktop, System 7.5 maintains automated folders, so the Apple Menu Items Alias can be used to get to “Recent Documents”. The “Recent Servers” can be used to log onto to any server without leaving the application that you are running.

- Mark Tillinghast
XXCAL, Testing And Systems Division
mark_tillinghast@lamg.com

Debugging For Fun and Profit

When you have routines that return OSErrs, finish them with the following bit of code:

 
ReportError ( err );
return err;
}

which is defined as:

#ifdef qDEBUG
#define ReportError(err) do { if (err != noErr ) DebugStr ( “
\pError” ); } while (false)
#else
#define ReportError(err)  /* nothing */
#endif

With this macro, you can tell every time that one of your routines returns an error, and it’s easy to follow your error handling code.

- Marshall Clow
Aladdin Systems

What’s My Modifier?

To quickly get the status of modifier keys, use these simple lines:

typedef struct kbd_bits {
 int command : 1;
 int : 5;
 int space : 1;
 int tab : 1;
 int : 4;
 control : 1;
 option : 1;
 capslock : 1;
 shift : 1;
} kbd_bits;

#define KeyModifiers (*(kbd_bits *)0x17A)

Then you can say simply:

if (KeyModifiers.control) {
 Debugger(); // drop into a debugger
}

This works across all Macs, including foreign versions and keyboard maps. For maximum compatibility with a minimal speed hit, call GetOSEvent with a null event mask and examine the modifiers field of the event returned.

- Jorg Brown
The Mac Group

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

BBEdit 11.6.5 - Powerful text and HTML e...
BBEdit is the leading professional HTML and text editor for the Mac. Specifically crafted in response to the needs of Web authors and software developers, this award-winning product provides a... Read more
OmniGraffle 7.3 - Create diagrams, flow...
OmniGraffle helps you draw beautiful diagrams, family trees, flow charts, org charts, layouts, and (mathematically speaking) any other directed or non-directed graphs. We've had people use Graffle to... Read more
OmniGraffle Pro 7.3 - Create diagrams, f...
OmniGraffle Pro helps you draw beautiful diagrams, family trees, flow charts, org charts, layouts, and (mathematically speaking) any other directed or non-directed graphs. We've had people use... Read more
DEVONthink Pro 2.9.11 - Knowledge base,...
DEVONthink Pro is your essential assistant for today's world, where almost everything is digital. From shopping receipts to important research papers, your life often fills your hard drive in the... Read more
DiskCatalogMaker 6.8.1 - Catalog your di...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast Finder-like intuitive look and feel Super-fast search algorithm Can compress catalog data for... Read more
Tunnelblick 3.7.0 - GUI for OpenVPN.
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
Adobe Dreamweaver CC 2017 17.0.2.9391 -...
Dreamweaver CC 2017 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Dreamweaver customer). Adobe Dreamweaver CC 2017 allows you to... Read more
Adobe Animate CC 2017 16.2.0 - Advanced...
Animate CC 2017 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Flash Professional customer). Animate CC 2017 (was Flash CC) lets you... Read more
A Better Finder Rename 10.15 - File, pho...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
Creative Kit 1.1 - $149.99
Creative Kit 2016--made exclusively for Mac users--is your ticket to the most amazing images you've ever created. With a variety of powerful tools at your fingertips, you'll not only repair and fine-... Read more

Power Rangers: Legacy Wars beginner...
Rita Repulsa is back, but this time she's invading your mobile phone in Power Rangers: Legacy Wars. What looks to be a straightforward beat 'em up is actually a tough-as-nails multiplayer strategy game that requires some deft tactical maneuvering.... | Read more »
Hearthstone celebrates the upcoming Jour...
Hearthstone gets a new expansion, Journey to Un'Goro, in a little over a week, and they'll be welcoming the Year of the Mammoth, the next season, at the same time. There's a lot to be excited about, so Blizzard is celebrating in kind. Players will... | Read more »
4 smart and stylish puzzle games like Ty...
TypeShift launched a little over a week ago, offering some puzzling new challenges for word nerds equipped with an iOS device. Created by Zach Gage, the mind behind Spelltower, TypeShift boasts, like its predecessor, a sleak design and some very... | Read more »
The best deals on the App Store this wee...
Deals, deals, deals. We're all about a good bargain here on 148Apps, and luckily this was another fine week in App Store discounts. There's a big board game sale happening right now, and a few fine indies are still discounted through the weekend.... | Read more »
The best new games we played this week
It's been quite the week, but now that all of that business is out of the way, it's time to hunker down with some of the excellent games that were released over the past few days. There's a fair few to help you relax in your down time or if you're... | Read more »
Orphan Black: The Game (Games)
Orphan Black: The Game 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dive into a dark and twisted puzzle-adventure that retells the pivotal events of Orphan Black. | Read more »
The Elder Scrolls: Legends is now availa...
| Read more »
Ticket to Earth beginner's guide: H...
Robot Circus launched Ticket to Earth as part of the App Store's indie games event last week. If you're not quite digging the space operatics Mass Effect: Andromeda is serving up, you'll be pleased to know that there's a surprising alternative on... | Read more »
Leap to victory in Nexx Studios new plat...
You’re always a hop, skip, and a jump away from a fiery death in Temple Jump, a new platformer-cum-endless runner from Nexx Studio. It’s out now on both iOS and Android if you’re an adventurer seeking treasure in a crumbling, pixel-laden temple. | Read more »
Failbetter Games details changes coming...
Sunless Sea, Failbetter Games' dark and gloomy sea explorer, sets sail for the iPad tomorrow. Ahead of the game's launch, Failbetter took to Twitter to discuss what will be different in the mobile version of the game. Many of the changes make... | Read more »

Price Scanner via MacPrices.net

Is Apple Planning An iPhone Based Modular Doc...
Today’s more powerful and larger-screened smartphones and phablets are becoming the default anchor computing device for more and more users computing devices, but even a five or six inch panel is not... Read more
Razer Launches New Razer Blade Pro World’s Fi...
Razer, the gaming and high performance hardware specialists, have announced the new Razer Blade Pro laptop — the first laptop to be qualified for THX Mobile Certification, an accreditation reserved... Read more
Gro CRM’s Apple Small Business Mac And iOS CR...
Gro Software, developers of the Mac CRM software for small business and enterprise, are included in FinancesOnline 2017 CRM Rising Stars and Great User Experience lists by business software review... Read more
Deal alert! 15-inch and 13-inch MacBook Pros...
B&H Photo has the new 2016 15″ and 13″ Apple MacBook Pros in stock today and on sale for up to $200 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.7GHz Touch Bar... Read more
Save up to $420 on a new MacBook Pro with App...
Apple is offering Certified Refurbished 2016 15″ and 13″ MacBook Pros, including some Touch Bar models, for up to $420 off original MSRP. An Apple one-year warranty is included with each model, and... Read more
12-inch 1.2GHz Retina MacBooks on sale for $1...
B&H has 12″ 1.2GHz Retina MacBooks on sale for up to $200 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 12″ 1.2GHz Space Gray Retina MacBook: $1449 $150 off MSRP - 12″ 1.... Read more
Is A New 10.5-inch iPad Still Coming In April...
There was no sign or mention of a long-rumored and much anticipated 10.5-inch iPad Pro in Apple’s product announcements last week. The exciting iPad news was release of an upgraded iPad Air with a... Read more
T-Mobile’s Premium Device Protection Now Incl...
Good news for T-Mobile customers who love their iPhones and iPads. The “Un-carrier” has become the first national wireless company to give customers AppleCare Services at zero additional cost as part... Read more
FileWave Ensures Support for Latest Apple OS...
FileWave multi-platform device management providers announced support for Apple’s release yesterday of iOS 10.3, macOS Sierra 10.12.4, and tvOS 11.2. FileWave has a history of providing zero-day... Read more
Use Apple’s Education discount to save up to...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free: -... Read more

Jobs Board

Fulltime aan de slag als shopmanager in een h...
Ben jij helemaal gek van Apple -producten en vind je het helemaal super om fulltime shopmanager te zijn in een jonge en hippe elektronicazaak? Wil jij werken in Read more
Fulltime aan de slag als shopmanager in een h...
Ben jij helemaal gek van Apple -producten en vind je het helemaal super om fulltime shopmanager te zijn in een jonge en hippe elektronicazaak? Wil jij werken in Read more
Desktop Analyst - *Apple* Products - Montef...
…technology to improve patient care. JOB RESPONSIBILITIES: Provide day-to-day support for Apple Hardware and Software in the environment based on the team's support Read more
*Apple* Mobile Master - Best Buy (United Sta...
**493168BR** **Job Title:** Apple Mobile Master **Location Number:** 000827-Denton-Store **Job Description:** **What does a Best Buy Apple Mobile Master do?** At Read more
Fulltime aan de slag als shopmanager in een h...
Ben jij helemaal gek van Apple -producten en vind je het helemaal super om fulltime shopmanager te zijn in een jonge en hippe elektronicazaak? Wil jij werken in Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.