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

MacTutor

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;
 
    oldA5=SetCurrentA5();
    gCursorTask->vblCount=gSpeed;
    if (gSpinCycles && !(*(Byte*)0x8cd)){
        gSpinCycles--;
        (*gCurrentHdl)->index++;
        (*gCurrentHdl)->index%=(*gCurrentHdl)->n;
        if (gColorCursor){
            SetCCursor((*gCurrentHdl)->frame[(*gCurrentHdl)->index].cursorHdl);
        }else{
            SetCursor(*(*gCurrentHdl)->frame[(*gCurrentHdl)->index].cursorHdl);
        }
    }
    SetA5(oldA5);
}

HOTWIRE Labs Address

Kirk Chase

MacTutor

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

HOTWIRE Labs

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);
 CtoPstr(tempBuf);
 DebugStr(tempBuf);
}

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

Latest Forum Discussions

See All

Pack a magnifying glass and practice you...
Somehow it has already been a year since Torchlight: Infinite launched, and XD Games is celebrating by blending in what sounds like a truly fantastic new update. Fans of Cthulhu rejoice, as Whispering Mist brings some horror elements, and tests... | Read more »
Summon your guild and prepare for war in...
Netmarble is making some pretty big moves with their latest update for Seven Knights Idle Adventure, with a bunch of interesting additions. Two new heroes enter the battle, there are events and bosses abound, and perhaps most interesting, a huge... | Read more »
Make the passage of time your plaything...
While some of us are still waiting for a chance to get our hands on Ash Prime - yes, don’t remind me I could currently buy him this month I’m barely hanging on - Digital Extremes has announced its next anticipated Prime Form for Warframe. Starting... | Read more »
If you can find it and fit through the d...
The holy trinity of amazing company names have come together, to release their equally amazing and adorable mobile game, Hamster Inn. Published by HyperBeard Games, and co-developed by Mum Not Proud and Little Sasquatch Studios, it's time to... | Read more »
Amikin Survival opens for pre-orders on...
Join me on the wonderful trip down the inspiration rabbit hole; much as Palworld seemingly “borrowed” many aspects from the hit Pokemon franchise, it is time for the heavily armed animal survival to also spawn some illegitimate children as Helio... | Read more »
PUBG Mobile teams up with global phenome...
Since launching in 2019, SpyxFamily has exploded to damn near catastrophic popularity, so it was only a matter of time before a mobile game snapped up a collaboration. Enter PUBG Mobile. Until May 12th, players will be able to collect a host of... | Read more »
Embark into the frozen tundra of certain...
Chucklefish, developers of hit action-adventure sandbox game Starbound and owner of one of the cutest logos in gaming, has released their roguelike deck-builder Wildfrost. Created alongside developers Gaziter and Deadpan Games, Wildfrost will... | Read more »
MoreFun Studios has announced Season 4,...
Tension has escalated in the ever-volatile world of Arena Breakout, as your old pal Randall Fisher and bosses Fred and Perrero continue to lob insults and explosives at each other, bringing us to a new phase of warfare. Season 4, Into The Fog of... | Read more »
Top Mobile Game Discounts
Every day, we pick out a curated list of the best mobile discounts on the App Store and post them here. This list won't be comprehensive, but it every game on it is recommended. Feel free to check out the coverage we did on them in the links below... | Read more »
Marvel Future Fight celebrates nine year...
Announced alongside an advertising image I can only assume was aimed squarely at myself with the prominent Deadpool and Odin featured on it, Netmarble has revealed their celebrations for the 9th anniversary of Marvel Future Fight. The Countdown... | Read more »

Price Scanner via MacPrices.net

Every model of Apple’s 13-inch M3 MacBook Air...
Best Buy has Apple 13″ MacBook Airs with M3 CPUs in stock and on sale today for $100 off MSRP. Prices start at $999. Their prices are the lowest currently available for new 13″ M3 MacBook Airs among... Read more
Sunday Sale: Apple iPad Magic Keyboards for 1...
Walmart has Apple Magic Keyboards for 12.9″ iPad Pros, in Black, on sale for $150 off MSRP on their online store. Sale price for online orders only, in-store price may vary. Order online and choose... Read more
Apple Watch Ultra 2 now available at Apple fo...
Apple has, for the first time, begun offering Certified Refurbished Apple Watch Ultra 2 models in their online store for $679, or $120 off MSRP. Each Watch includes Apple’s standard one-year warranty... Read more
AT&T has the iPhone 14 on sale for only $...
AT&T has the 128GB Apple iPhone 14 available for only $5.99 per month for new and existing customers when you activate unlimited service and use AT&T’s 36 month installment plan. The fine... Read more
Amazon is offering a $100 discount on every M...
Amazon is offering a $100 instant discount on each configuration of Apple’s new 13″ M3 MacBook Air, in Midnight, this weekend. These are the lowest prices currently available for new 13″ M3 MacBook... Read more
You can save $300-$480 on a 14-inch M3 Pro/Ma...
Apple has 14″ M3 Pro and M3 Max MacBook Pros in stock today and available, Certified Refurbished, starting at $1699 and ranging up to $480 off MSRP. Each model features a new outer case, shipping is... Read more
24-inch M1 iMacs available at Apple starting...
Apple has clearance M1 iMacs available in their Certified Refurbished store starting at $1049 and ranging up to $300 off original MSRP. Each iMac is in like-new condition and comes with Apple’s... Read more
Walmart continues to offer $699 13-inch M1 Ma...
Walmart continues to offer new Apple 13″ M1 MacBook Airs (8GB RAM, 256GB SSD) online for $699, $300 off original MSRP, in Space Gray, Silver, and Gold colors. These are new MacBook for sale by... Read more
B&H has 13-inch M2 MacBook Airs with 16GB...
B&H Photo has 13″ MacBook Airs with M2 CPUs, 16GB of memory, and 256GB of storage in stock and on sale for $1099, $100 off Apple’s MSRP for this configuration. Free 1-2 day delivery is available... Read more
14-inch M3 MacBook Pro with 16GB of RAM avail...
Apple has the 14″ M3 MacBook Pro with 16GB of RAM and 1TB of storage, Certified Refurbished, available for $300 off MSRP. Each MacBook Pro features a new outer case, shipping is free, and an Apple 1-... Read more

Jobs Board

*Apple* Systems Administrator - JAMF - Activ...
…**Public Trust/Other Required:** None **Job Family:** Systems Administration **Skills:** Apple Platforms,Computer Servers,Jamf Pro **Experience:** 3 + years of Read more
IT Systems Engineer ( *Apple* Platforms) - S...
IT Systems Engineer ( Apple Platforms) at SpaceX Hawthorne, CA SpaceX was founded under the belief that a future where humanity is out exploring the stars is Read more
Nurse Anesthetist - *Apple* Hill Surgery Ce...
Nurse Anesthetist - Apple Hill Surgery Center Location: WellSpan Medical Group, York, PA Schedule: Full Time Sign-On Bonus Eligible Remote/Hybrid Regular Apply Now Read more
Housekeeper, *Apple* Valley Village - Cassi...
Apple Valley Village Health Care Center, a senior care campus, is hiring a Part-Time Housekeeper to join our team! We will train you for this position! In this role, Read more
Sublease Associate Optometrist- *Apple* Val...
Sublease Associate Optometrist- Apple Valley, CA- Target Optical Date: Apr 20, 2024 Brand: Target Optical Location: Apple Valley, CA, US, 92307 **Requisition Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.