TweetFollow Us on Twitter

Dec 93 Tips, Tidbits
Volume Number:9
Issue Number:12
Column Tag:Tips & Tidbits

Tips & Tidbits

By Neil Ticktin, Editor-in-Chief

This column is your opportunity to spread the word about little bits of information that you find out about. These tidbits can be programming related or they can be user tips that are particularly useful to programmers.

MacTech Magazine will pay $25 for every tip used, and $50 for the Tip of the Month. Or you can take your award in orders or subscriptions.

To submit a tip, send in a letter to the magazine. E-mail is our preferred method, but feel free to send something via the US Mail. See page two for all addresses. If you do send snail mail, enclose a printed copy and a disk copy of the letter so that it does not have to be retyped.

Tip of the Month: Accelerating MPW's Startup Sequence

This trick is described in the Examples folder that comes with MPW. But in talking to other users, I was surprised to find few people know about it, and even fewer use it.

When MPW is launched, it executes a script named “Startup,” which sets up environment variables, aliases, custom menus, and so forth. This can take from several seconds to over a minute.

It is easy to optimize this startup sequence. After launching MPW normally, copy the following lines into the MPW Worksheet window. Then highlight them as a block and press Enter:

/* 1 */

   Rename "{MPW}"Startup "{MPW}"Startup.Old
   End > "{MPW}"Startup

This creates an optimized Startup script that will typically execute two to ten times faster than the original. The initial “Rename” command saves the original Startup script, so you can revert to it if you decide you don’t like the results. But if you do “before and after” timings, I think you’ll be happy with the speed improvement.

There are a couple of caveats though. First, the optimized Startup script is not organized and commented the same way the original is. If you frequently change your MPW configuration, you might find the optimized script harder to read and edit. Or you might find it to be easier; the point is that it is different.

Second, if you have UserStartup files that are often modified (such as UserStartup•RunMenu, described in MacTech Magazine, October, 1993), you may wish to add a line to the end of the optimized Startup script to forcibly execute the UserStartup commands. With UserStartup•RunMenu as an example, here’s what the command would look like:

        Execute "{PrefsFolder}"UserStartup•RunMenu

In doing this, you will cause some startup commands to be executed more than once (since some commands from the UserStartup will appear in the optimized Startup script as well). As a final “tweak,” you should then edit the optimized Startup script to delete any commands which will be carried out by forcibly executed UserStartup scripts.

- Lee David Rimar, Absoft Corporation

Strings that go both ways

When writing programs in C on the Macintosh, one thing that we need to deal with is the two possible formats of strings: C-style and Pascal-style. To save the repeated conversion time between the two formats, I sometimes use a format I call the two-in-one format that has both at once.

The C-style string uses a terminating zero character (null) at the end of the string to mark it’s length. The Pascal-style string uses a length byte as the first byte of the string (see figure). Both are allocated by allocating the space for the maximum number of characters the string will hold plus one for either the length byte or the termination byte. My two-in-one format uses both a length byte as it’s first byte and the zero byte as it’s last. To allocate this, take the data size and add two for both the Pascal-style length byte and the C-style terminator. The illustration shows how the length byte, string data, and terminator are laid out.

To use this as a Pascal string, simply use it normally. To use it as a C string, pass the string address as string + 1. Of course, if the size of the string is changed, then either the length byte or the terminator will need to adjusted. If you use calls that treat it as a C string, then the length byte will need adjusting. If you use Pascal-style calls, the terminator will need adjusting. The adjusting isn’t always as hard as you might think.

The following code fragment illustrates using the two-in-one string format:

/* 2 */

Str255  stringOne;
char  stringTwo[50];

/*   #1 Toolbox call uses Pascal-style string. */
GetIText (dialogItemHandle, stringOne);
stringOne[stringOne[0] + 1] = ’\0’;     // Add term. byte
/*   #2 Uses C-style string and returns the num. of characters. */
stringTwo[0] = sprintf (stringTwo + 1, “foobar”);
/*   #3 Two-in-one style, notice the length plus two. */
BlockMove (stringOne, stringTwo, stringOne[0] + 2);

In #1, the toolbox call returns a Pascal-style string, so, for the two-in-one format we’ve got to add the terminator. We know that stringOne[0] is the length byte and we know that stringOne[length] is the last byte of data in the string. So, the length plus one is the terminator byte.

In #2, we’re using the string as a C-style string. Notice that the C-style string starts at an offset of one, this avoids the Pascal-style length byte. Fortunately, sprintf returns the number of bytes (characters) written if there’s no error so we can use it to adjust the length byte. Other C library calls like printf, scanf and their derivatives also return the number of characters processed.

In #3, we’re using the Toolbox call BlockMove() to copy a two-in-one format string. Since the length is the length of the data, we’ve got to add two to allow for the length byte and the terminator byte.

I’ve found that judicious use of this string format can save a lot of conversion in string-heavy programs.

- Malcolm Teas


In Think Pascal, the option key allows you to “step-step” through the code. Hold down the option key and pull down the RUN menu. You will see the step-step option. Step-step walks through your source code one line at a time, stepping into functions and procedures. It’s like a guided tour through your own program. Hold down the option key and browse through the Think Pascal menus. You may be surprised how much the option key modifies in the menus.

- Lillian Thompson, Reno, Nevada


Community Search:
MacTech Search:

Software Updates via MacUpdate

TruckSimulation 16 guide: How to succeed...
Remember those strangely enjoyable truck missions in Grand Theft Auto V whereit was a disturbing amount of fun to deliver cargo? TruckSimulation 16 is reminiscent of that, and has you play the role of a truck driver who has to deliver various... | Read more »
The best GIF making apps
Animated GIFs have exploded in popularity recently which is likely thanks to a combination of Tumblr, our shorter attention spans, and the simple fact they’re a lot of fun. [Read more] | Read more »
The best remote desktop apps for iOS
We've been sifting through the App Store to find the best ways to do computer tasks on a tablet. That gave us a thought - what if we could just do computer tasks from our tablets? Here's a list of the best remote desktop apps to help you use your... | Read more »
Warhammer 40,000: Freeblade guide - How...
Warhammer 40,000: Freebladejust launched in the App Store and it lets you live your childhood dream of blowing up and slashing a bunch of enemies as a massive, hulking Space Marine. It's not easy being a Space Marine though - and particularly if... | Read more »
Gopogo guide - How to bounce like the be...
Nitrome just launched a new game and, as to be expected, it's a lot of addictive fun. It's called Gopogo, and it challenges you to hoparound a bunch of platforms, avoiding enemies and picking up shiny stuff. It's not easy though - just like the... | Read more »
Sago Mini Superhero (Education)
Sago Mini Superhero 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: KAPOW! Jack the rabbit bursts into the sky as the Sago Mini Superhero! Fly with Jack as he lifts impossible weights,... | Read more »
Star Wars: Galaxy of Heroes guide - How...
Star Wars: Galaxy of Heroes is all about collecting heroes, powering them up, and using them together to defeat your foes. It's pretty straightforward stuff for the most part, but increasing your characters' stats can be a bit confusing because it... | Read more »
The best cooking apps (just in time for...
It’s that time of year again, where you’ll be gathering around the dinner table with your family and a huge feast in front of you. [Read more] | Read more »
Square Rave guide - How to grab those te...
Square Rave is an awesome little music-oriented puzzle game that smacks of games like Lumines, but with its own unique sense of gameplay. To help wrap your head around the game, keep the following tips and tricks in mind. [Read more] | Read more »
Snowboard Party 2 (Games)
Snowboard Party 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Crowned the best snowboarding game available on the market, Snowboard Party is back to fulfill all your adrenaline needs in... | Read more »

Price Scanner via

Holiday weekend: Apple Watch on sale for $50-...
B&H Photo has the Apple Watch on sale today for $50-$100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - Apple Watch Sport: $50 off - Apple Watch: $50-$100 off Read more
Holiday weekend: iPad Air 2s on sale for up t...
B&H Photo has iPad Air 2s on sale for up to $80 off MSRP including free shipping plus NY sales tax only: - 16GB iPad Air 2 WiFi: $459 $40 off - 64GB iPad Air 2 WiFi: $569 $30 off - 128GB iPad Air... Read more
Holiday weekend Mac sales roundup: B&H Ph...
B&H Photo continues to have all new Macs on sale for up to $500 off MSRP as part of their Black Friday/Holiday weekend sale. Shipping is free, and B&H charges NY tax only: - 15″ 2.2GHz Retina... Read more
iMobie Releases its Ace iOS Cleaner PhoneClea...
iMobie Inc. has announced the new update of PhoneClean 4, its iOS cleaner designed to reclaim wasted space on iPhone/iPad for use and keep the device fast. Alongside, iMobie hosts a 3-day giveaway of... Read more
U.S. Cellular Offering iPad Pro
U.S. Cellular today announced that it is offering the new iPad Pro with Wi-Fi + Cellular, featuring a 12.9-inch Retina display with 5.6 million pixels — the most ever in an iOS device. U.S. Cellular... Read more
Newegg Canada Unveils Black Friday Deals for...
Newegg Canada is offering more than 1,000 deep discounts to Canadian customers this Black Friday, available now through Cyber Monday, with new deals posted throughout the week. “Black Friday is... Read more
Black Friday: Macs on sale for up to $500 off...
BLACK FRIDAY B&H Photo has all new Macs on sale for up to $500 off MSRP as part of their early Black Friday sale including free shipping plus NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $... Read more
Black Friday: Up to $125 off iPad Air 2s at B...
BLACK FRIDAY Walmart has the 16GB iPad Air 2 WiFi on sale for $100 off MSRP on their online store. Choose free shipping or free local store pickup (if available): - 16GB iPad Air 2 WiFi: $399, save $... Read more
Black Friday: iPad mini 4s on sale for $100 o...
BLACK FRIDAY Best Buy has iPad mini 4s on sale for $100 off MSRP on their online store for Black Friday. Choose free shipping or free local store pickup (if available): - 16GB iPad mini 4 WiFi: $299.... Read more
Black Friday: Apple Watch for up to $100 off...
BLACK FRIDAY Apple resellers are offering discounts and bundles with the purchase of an Apple Watch this Black Friday. Below is a roundup of the deals being offered by authorized Watch resellers:... Read more

Jobs Board

Specialist *Apple* /Mac Desktop - University...
…technical support, expertise and user training for a variety of Apple /Macintosh hardware, software and devices.Researches, analyzes and resolves complex Apple Read more
*Apple* Site Security Manager - Apple (Unite...
# Apple Site Security Manager Job Number: 42975010 Culver City, Califo ia, United States Posted: Oct. 2, 2015 Weekly Hours: 40.00 **Job Summary** The Apple Site Read more
WiSE *Apple* Pay Quality Engineer - Apple (...
# WiSE Apple Pay Quality Engineer Job Number: 44313381 Santa Clara Valley, Califo ia, United States Posted: Nov. 13, 2015 Weekly Hours: 40.00 **Job Summary** Join our Read more
Holiday Retail Associate with *Apple* Knowl...
…and assertive.Someone who can troubleshoot iOS devices (iPhone and iPad) and Apple Mail issues.Someone who can offer solutions.Someone who can work weekends.Someone with Read more
*Apple* Systems Engineer (Mclean, VA and NYC...
Summary:Assist in providing strategic direction and technical leadership within the Apple portfolio, including desktops, laptops, and printing environment. This person Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.