TweetFollow Us on Twitter

Jun 91 Letters
Volume Number:7
Issue Number:6
Column Tag:Letters

Sorry, no Yerk

By Kirk Chase, Editor

Yerk is NOT on Disk

Kirk Chase


Jörg Langowski, in his March column, indicated that the sources for NEON, now public domain and called “Yerk”, would be put that month’s source code disk. It did not come in with Mr. Langowski’s materials, but we have obtained it. Unfortunately, Yerk is much to large, even after compression to place on anything but a high density floppy. Therefore, Yerk will NOT be distributed on the source code disk. We obtained it on America OnLine. Other BBS and on-line services should be carrying Yerk also. We are sorry that we are not able to distribute it to you.

Animated Cursor Corrections

Rich Lesh

Bridgeton, MO

In my March ’91 article “Animated Color Cursors,” I mentioned that you must be careful to avoid re-entrant conditions with the SetCursor() calls.

Sometimes this is difficult even in the most well behaved programs. I was informed by a reader, Joe Schwartz, that Apple has posted a tidbit of information that can solve this problem. According to the Q&A Stack that Apple distributes, there is a low memory byte, CrsrBusy at 0x8CD, that indicates whether or not the cursor is currently busy, i.e. shouldn’t be changed. The following correction to the code published in March makes use of this global to prevent any calls to SetCursor() when the cursor is busy.

This prevents any cursor fragments from appearing on the screen.

/* 1 */

static pascal void SpinCursorTask()
    long oldA5;
    if (gSpinCycles && !(*(Byte*)0x8cd)){
        if (gColorCursor){

HOTWIRE Labs Address

Kirk Chase


HOTWIRE Labs’ address was inadvertently left off in the April issue. We regret this sincerely as their hardware debugger, Xtrap, is a great developer’s product. Their address is


8912 Jamesburg

Witchita, KS 67212

(316) 838-8849

AppleLink: D4527

INIT Mr. Bus Error

Tom Nielsen

Recommended Testing

336 Cernon St.

Vacaville, CA 95688

In February’s issue, Dave Dunham said “I don’t like them (programs) generating bus errors, having to reboot without Mr. Bus Error and rerunning the programs”. Being a programmer and tester myself, I can understand Mr. Dunham’s frustration; however, there is a way to continue the program’s execution as if INIT Mr. Bus Error were not installed.

In MacsBug, examine the registers on the left looking for the characteristic 00F0F0F1 that INIT Mr. Bus Error uses. (Note: Sometimes the register is 00F0F0Fx, where x is some number besides 1. This happens when the application uses the handle as a handle to an array or string). If this value is in register A0, then you would type “A0=0;g.” If it’s in A1, then you’d type “A1=0;g.” That’s it. The program continues as if INIT Mr. Bus Error were not installed. In fact, I type this line so often that I’ve created MacsBug macros to do it for me. These macros clear out register A0, A1 or both and then continue.

[Tom has included three resources that can be added to MacsBug’s prefs file “Debugger Prefs” (found in the System Folder) which may be found on this month’s source disk. Pasting these resources into this file and rebooting, adds the clear Mr Bus Error commands to the list of macros.

Macros Meaning Expansion

azg A Zero Go A0=0;g

aog A One Go A1=0;g

abg A Both Go A0=0;A1=0;g

The template for editing these resources should already be in your Debugger Prefs file.-ed and Tom]

More Debugging Tips

Mike Morton

Honolulu, HI

Some comments on Rex Reinhart’s letter in the March issue:

First, you needn’t use “asm” to drop into the debugger. Think C has a Debugger() trap defined for you, so just put this line in your source:

/* 2 */

Debugger(); /* invoke debugger */

An equally useful trap is the DebugStr(), which takes a single Pascal-string argument. You can “print” simple messages with:

/* 3 */

DebugStr(“\phello, world!”);

or you can print out more useful information to print variables or other values:

/* 4 */

 char tempBuf[100];
 sprintf(tempBuf, “x is %d”, x);

Don’t forget the CtoPstr() call to convert the string from C to Pascal format.

An advantage of this kind of output is that during repeated debugging sessions you needn’t enter your variables into the Data window in the Think C debugger. Or if you don’t have the memory for the debugger, or are debugging a standalone application, this stuff is handy. (of course, if you have a text window for debugging output, you don’t usually need DebugStr().)

Another trick is the equivalent of Think C’s conditional breakpoints. Suppose you have a loop which is locking up after many iterations. If you press the Interrupt switch, you’ll get Macsbug or TMON, not the Think C debugger. Instead, put this line anywhere in the loop:

/* 5 */

if (optionKeyDown()) DeBugger();

(Here, optionKeyDown() is some function you write which tests for the option key.) Run your application until it seems to hang up, then hold down the option key-now you’re in the Think C debugger.

Lastly, be sure to remove all these calls before you distribute your application!

[Still, Think C would definitely be friendlier if its debugger were more like Think Pascal. I feel something like selecting a variable and the a menu command to examine its contents would be nice. I suppose something a little more interactive than DebugStr().-ed]

Call For Articles

Kirk Chase

Editor, MacTutor

Every so often (about five or six times a day), I am asked what I would like to see in the way of articles for MacTutor. At that time, I pull out my editorial calendar (which is scribbled on with a multitude of changes) to read off some of the upcoming topics. Here are a number of requests from readers:

• Programming for modules. This would include such things as given the application’s working directory, a folder name of where the modules are located, and a filter proc, return a path (or directory) and list of filtered files to be used later. Also, we have had articles on external functions/modules in January and February of 1990, but one on file format filters would also be nice.

• Dialog enhancements such as a preview picture.

• A great article or two on the in’s and out’s of the File Manager, Resource Manager, Finder information and MultiFinder information (such as proper use of the SCC ports).

• System 7 quirks, tips and discussions.

• 32-bit QuickDraw, animation (B&W/Color), sound.

• Networking/Groupware articles.

• Neat DEF’s.

And the list goes on and on.

So if you have an elegant solution to a problem, send it in. You’ll gain recognition and inspire others.

GUI Wars

XVT Software, Inc.

1800 30th St., Box 17665

Boulder, CO 80308

(303) 443-4223

One way to reach a bigger market for your product is to publish it on multiple platforms. This is called, “cross development”. This has been growing steadily for the past few years. Even on the Macintosh, there are different platforms such as A/UX to develope for.

The problem with cross development is differing machine architectures and user interfaces. You can reuse some of your code, but it is hard to separate the Mac Toolbox from your code; this makes it difficult to port your code over. You could go to the lowest level of character I/O (PLEASE DON’T!), but that is not why you got started on the Macintosh. You could even rewrite everything from scratch.

Another solution offers an elegant way to port your graphical program over to another windowing environment. Enter XVT, or the Extensible Virtual Toolkit, from XVT Software Inc. With XVT, you can obtain GUI portability. Now you can develope C/C++ code for THINK or MPW. Then, you take that same source over to your other platform environment and compile without a whole lot of changes.

There is a down side to this GUI solution. The first is the cost factor; each library for a particular platform costs about $800; to get the source it is around $5000; also a license is required for distribution. This price does include an annual technical support and update program.

The second problem and third problem are speed degradation and capability limitations. These problems are only natural. One would expect a slight slow down in execution speed because of the higher-level calls. Also, some features beyond the normal ones are not implemented due to the need for cross compatibility.

Still, these factors are probably not large when faced with the potential savings in time/resources and potential gains in new markets. I know now that AppMaker now generates code for XVT. This makes development time go down dramatically. Imagine using AppMaker to get the user interface down, and then generating code that is cross compatible. I imagine dollar signs.


Community Search:
MacTech Search:

Software Updates via MacUpdate

Suitcase Fusion 6 17.3.0 - Font manageme...
Suitcase Fusion 6 is the creative professional's font manager. Every professional font manager should deliver the basics: spectacular previews, powerful search tools, and efficient font organization... Read more
Nisus Writer Pro 2.1.2 - Multilingual wo...
Nisus Writer Pro is a powerful multilingual word processor, similar to its entry level products, but brings new features such as table of contents, indexing, bookmarks, widow and orphan control,... Read more
calibre 2.40.0 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Vivaldi - An advanced browser...
Vivaldi is a browser for our friends. In 1994, two programmers started working on a web browser. Our idea was to make a really fast browser, capable of running on limited hardware, keeping in mind... Read more
OmniPlan 3.0 - Robust project management...
With OmniPlan, you can create logical, manageable project plans with Gantt charts, schedules, summaries, milestones, and critical paths. Break down the tasks needed to make your project a success,... Read more
Yummy FTP 1.11 - FTP/SFTP/FTPS client fo...
Yummy FTP is an FTP + SFTP + FTPS file transfer client which focuses on speed, reliability and productivity. Whether you need to transfer a few files or a few thousand, schedule automatic backups, or... Read more
Tweetbot 2.1 - Popular Twitter client. (...
Tweetbot is a full-featured OS X Twitter client with a lot of personality. Whether it's the meticulously-crafted interface, sounds and animation, or features like multiple timelines and column views... Read more
MacPilot 8.0 - Enable over 1,200 hidden...
MacPilot gives you the power of UNIX and the simplicity of Macintosh, which means a phenomenal amount of untapped power in your hands! Use MacPilot to unlock over 1,200 features, and access them all... Read more
Typinator 6.7 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
Adobe Lightroom 6.2 - Import, develop, a...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more

Balloony Land offers a fresh twist on th...
Balloony Land by Palringo offers a fresh twist on the match three genre and is out now on iOS and Android. First-off, you'll be popping balloons instead of crushing candy and the balloons will float up and fill the empty spaces instead of dropping... | Read more »
Sago Mini Babies (Education)
Sago Mini Babies 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: Introducing the Sago Mini babies. Boys and girls love caring for these adorable characters. Feed Robin her favorite mush... | Read more »
PAUSE - Relaxation at your fingertip (H...
PAUSE - Relaxation at your fingertip 1.1 Device: iOS iPhone Category: Healthcare & Fitness Price: $1.99, Version: 1.1 (iTunes) Description: | Read more »
Super Sharp (Games)
Super Sharp 1.1 Device: iOS Universal Category: Games Price: $1.99, Version: 1.1 (iTunes) Description: Your finger has never been so sharp! Cut with skill to complete the 120 ingenious physics levels of Super Sharp and become a cut... | Read more »
Assembly - Graphic design for everyone...
Assembly - Graphic design for everyone 1.0 Device: iOS Universal Category: Photography Price: $2.99, Version: 1.0 (iTunes) Description: Assembly is the easiest most powerful design tool on the App Store. Create anything you can... | Read more »
Dub Dash (Games)
Dub Dash 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: ARE YOU READY FOR THE ULTIMATE CHALLENGE? UNIQUE SYMBIOSIS OF MUSIC AND GRAPHICS | Read more »
Leave Me Alone (Games)
Leave Me Alone 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: 33% off launch sale!!! Somewhere between the 1980s and 1990s there exists a world that never was. A world of skatepunks,... | Read more »
YAMGUN (Games)
YAMGUN 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: The invasion has begun! Protect the walls of the citadel against waves of enemies! But watch out, you will soon run out of ammo...... | Read more »
Chesh (Games)
Chesh 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: It’s like chess, only not at all. ***40% off for a limited time to celebrate our launch!*** Chesh is a game of skill, strategy, luck,... | Read more »
Dust: An Elysian Tail (Games)
Dust: An Elysian Tail 1.051 Device: iOS Universal Category: Games Price: $5.99, Version: 1.051 (iTunes) Description: *Dust: An Elysian Tail is a visually rich experience and thus requires devices with 1GB RAM**Please note that... | Read more »

Price Scanner via

TP-LINK Next-Gen Routers Support a Large Numb...
TP-LINK, specialists in consumer and business networking products, have announced the availability of Archer C2600, the company’s next-generation router featuring wireless AC, multi-user MIMO, and 4-... Read more
Apple’s Education discount saves up to $300 o...
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, and... Read more
Save up to $350 with Apple refurbished iMacs
Apple has Certified Refurbished iMacs available for up to $350 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $1949 $350 off MSRP - 27... Read more
Mac Pros on sale for up to $300 off MSRP
B&H Photo has Mac Pros on sale for up to $300 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2818.99, $181 off MSRP - 3.5GHz 6-core Mac Pro: $3699... Read more
5K iMacs on sale for up to $150 off MSRP, fre...
B&H Photo has the 27″ 3.3GHz 5K iMac on sale for $1899.99 including free shipping plus NY tax only. Their price is $100 off MSRP. They have the 27″ 3.5GHz 5K iMac on sale for $2149, $150 off MSRP... Read more
Twelve South Redesigns BookArc For Today’s Sm...
Twelve South has announced a redesigned version of their very first product, BookArc for MacBook. Tailored specifically for the newest generation of MacBooks, BookArc holds the new, smaller Apple... Read more
Phone 6s Tips & Tricks – Tips Book For iP...
Poole, United Kingdom based Tap Guides Ltd. has announced the release and immediate availability of iPhone 6s Tips & Tricks, an in-depth eBook available in the iBookstore that’s priced just $2.99... Read more
Apple refurbished 2014 13-inch Retina MacBook...
Apple has Certified Refurbished 2014 13″ Retina MacBook Pros available for up to $400 off original MSRP, starting at $979. An Apple one-year warranty is included with each model, and shipping is free... Read more
13-inch 2.5GHz MacBook Pro on sale for $994,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $994.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $105 off MSRP. Price valid... Read more
Is The iPad Pro Really A Serious Laptop Repla...
Probably not, at least for productive professionals and other power users. Steve Jobs declared that we’d entered the “post-PC Era” with the advent of the original iPad in 2010, a phrase we don’t hear... Read more

Jobs Board

*Apple* Desktop Analyst - KDS Staffing (Unit...
…work with some of the brightest engineers. Job Description Title: Apple Desktop AnalystPosition Type: Full-time PermanentLocation: White Plains, NYHot Points:Depth of Read more
*Apple* Retail Online, Customer Experience R...
**Job Summary** Apple Retail's Online Store sells Apple products to customers around the world. In addition to selling Apple products with unique services such Read more
Frameworks Engineer, *Apple* Watch - Apple...
**Job Summary** Join the team that is shaping the future of software development for Apple Watch! As a software engineer on the Apple Watch Frameworks team you will Read more
Senior Manager, Global Direct Marketing *App...
**Job Summary** Apple Retail is looking for an experienced Direct Marketing Leader to join its Marketing team. This position will take a leadership role in creating Read more
*Apple* Online Store Expansion - Apple (Unit...
**Job Summary** The Online Apple Store is seeking a person to lead its expansion into new countries. Based in Cupertino, CA, this person will develop and maintain an Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.