TweetFollow Us on Twitter

Dec 95 Tips
Volume Number:11
Issue Number:12
Column Tag:Tips & Tidbits

Tips & Tidbits

By Steve Sisak, Contributing Editor

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

TIP OF THE MONTH

Arguments To “s” In MacsBug

In MacsBug, the s [step] command will take an argument which is either a count or a condition on which to stop. This can be very useful for unwinding a twisty bit of code. For example, if you keep crashing in a particular spot, but you can’t tell how you got there or what happened just before, you can break before everything goes wrong and type


  s (pc == <badspot>)

Where badspot is where you know things are wrong. Macsbug will step through all of the instructions in between here and there. You can then examine the path taken in the scrollback or, if you turn on the log first, look at it all offline with an editor. With the newest versions of MacsBug, you can even step over mixed mode. Note that it’s possible for find weirder problems, too:


 s (a0 == 0)

will step until a0 equals 0.

 

 s (<addr>^ != <current value>)

will step until the long at <addr> changes.

You can use this trick to find a really wide variety of problems. Should you use this tip, donate my fee to the American Red Cross.

- Tim Dierks

They Said I Couldn’t
Return Errors From Constructors

I have read several times that “you can’t return an error from a constructor”. This is not entirely true. See the following code example:

class exampleClass : parentClass
{
  exampleClass( int arg1, OSErr& errOut );
    // initialization constructor
...etc....
};

exampleClass::exampleClass( int arg1, OSErr& errOut )
 : parentClass()  // parent class constructor explicitly called
 , memberData() // instance variable's explict constructor
{
//  errOut = noErr;  see note #4 below
  errOut = someSystemCall( arg1 );
}

void main ( void )
{
   OSErr  err;
   exampleClass  aVar( 12, err );
   if ( err != noErr ) 
   {....etc....
}

This example “obviously” returns error information.

However, errOut will NOT have a known value if the following occurs:

1. parentClass’s explicit constructor throws an exception.

2. memberData’s explicit constructor throws an exception.

3. someSystemCall throws an exception. This example used explicit contructor calls, but the same is true for implicit constructor calls to parent classes and member data varables.

4. if the errOut = noErr line is uncommented, then at least errOut can have a known value in the absence of other exceptions.

Of course, since main isn’t doing try/catch, then the test of err != noErr is not going to happen when an exception occurs, either.

- C. Keith Ray

Is Your App Windowshade Savvy?

Many apps change the cursor within certain areas of their windows. This may be to provide the crosshairs in a drawing window, or a hand cursor if something can be dragged in an area of your window. Unfortunately, many applications forget to check whether their window is windowshaded or not. If their window is windowshaded but still the front window, they go ahead and change the cursor anyway, leading to the effect of the cursor changing over “empty space.” Looks ugly. Here’s the fix:

if (EmptyRgn( ((WindowPeek)TheWindow)->contRgn )) 
//window shade has been used

Don’t change the cursor;

else

Go ahead and change the cursor;

In the above example, TheWindow is the windowptr to the window who’s areas we are changing the cursor for.

- Richard Unger and Eric Bourque

Shortcut to Open Header Files In CodeWarrior

Here is a feature that I’d long hoped for, and recently, by accident, found.

In Metrowerk’s IDE, typing ‘command tab’ will open the corresponding .h or .cp file. For example, if you’re working in a source file named “FileName.cp” typing ‘command tab’ will open “FileName.h”. This is an extremely useful feature that I hope Symantec will adopt.

- Norman Basha

Drop Into MacsBug at a Predictable Address

When dropping into MacsBug, I often find myself in the wrong application’s code. For example, lets say I want to force-quit the finder using “es” from MacsBug. (command-option-escape will quit and then restart the Finder). To make sure the Finder is the frontmost app, I hold the mouse down in one of the Finder’s menus and press the interrupt key, and I’m dropped in at a known location (a small loop within the menu manager). Not only that, but the current menu manager is emulated on PowerMacs, further ensuring my safety. Then a simple “es” quits the Finder.

- Damon Cokenias

Lock Your Libraries, Prevent Changes

Here’s a tip that may be obvious, but it’s useful, if somewhat simple.

If you don’t want to modify the standard libraries included in a development environment (the source to PowerPlant or TCL for example) you can use the following script to lock all the files. I use this script in MPW, but should work with ToolServer as well:

### First set the current directory to the folder containing the sources 
to lock
### note that this script does sub-folders also.
### replace "xxx" with your path, e.g., "HD:MPW:Interfaces:"
directory "Full path to the folder in which the files are:"

### Then set the lock bit to ON for all files which are of
### type 'TEXT' in the current directory and all sub-directories
### Notes:
###   remove "-r" to skip sub-directories
###   make the "L" lowercase ("l") to un-lock files
###   the -f is for full paths, -s to supress directory listings
SetFile -a L `files -r -f -s -t 'TEXT'`

Anyway, just thought I’d pass it on. It’s particularly useful while using a class browser like Object Master, where you can browse all classes and it’s easy to end up editing one of the supplied classes in PowerPlant/Think Class Library/MacApp.

- Tyler Morrison

[AppleScript also supports locking and unlocking of files. Simply modify the “locked” property of x, where x is a file alias or file name with: set the locked of file x to true

EdAsst - jtk]

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Monolingual 1.6.4 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. If you use your computer in only one (human) language, you... Read more
CleanApp 5.0 - Application deinstaller a...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Fantastical 2.0 - Create calendar events...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event details... Read more
Cocktail 8.2 - General maintenance and o...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
Direct Mail 4.0.4 - Create and send grea...
Direct Mail is an easy-to-use, fully-featured email marketing app purpose-built for OS X. It lets you create and send great looking email campaigns. Start your newsletter by selecting from a gallery... Read more
jAlbum Pro 12.6 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code!... Read more
jAlbum 12.6 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results Simply drag and drop photos into groups, choose a design... Read more
Lyn 1.5.9 - Lightweight image browser an...
Lyn is a lightweight and fast image browser and viewer designed for photographers, graphic artists and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it... Read more
Sublime Text 3080 - Sophisticated text e...
Sublime Text is a sophisticated text editor for code, markup, and prose. You'll love the slick user interface, extraordinary features, and amazing performance. Goto Anything. Use Goto Anything to... Read more
WALTR 1.0.11 - Drag-and-drop any media f...
WALTR is designed to make it easy to upload and convert any music or video file to an iPad or iPhone format for native playback. It supports a huge variety of media file types, including MP3, MP4,... Read more

Bio Inc's New Expansion is Infectin...
Bio Inc., by DryGin Studios, is the real time strategy game where you infect a human body with the worst virus your evil brain can design. Recently, the game was updated to add a whole lot of new features. Now you can play the new “Lethal”... | Read more »
The Monocular Minion is Here! Despicable...
Despicable Me: Minion Rush, by Gameloft, is introducing a new runner to the mix in their latest update. Now you can play as Carl, the prankster minion. Carl has a few new abilities to play with, including running at a higher speed from the start.... | Read more »
Dungeon of Madness (Games)
Dungeon of Madness 1.0.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.0 (iTunes) Description: Dungeon of Madness is an action game where you rotate tiles to create our own route. Help the hero by connecting the... | Read more »
Filters for iPhone (Photography)
Filters for iPhone 1.0 Device: iOS iPhone Category: Photography Price: $.99, Version: 1.0 (iTunes) Description: | Read more »
Jump'N'Shoot Attack (Games)
Jump'N'Shoot Attack 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: A mobile game for gamers! Join Louise Lightfoot, the legendary "Master of Jumping and Shooting", on her mission to save... | Read more »
Space Bounties Inc. (Games)
Space Bounties Inc. 1.4 Device: iOS Universal Category: Games Price: $1.99, Version: 1.4 (iTunes) Description: SuperGameDroid: 4/5 "Satisfying futuristic RPG combat, high replay value, and a heavy dose of nostalgia make Space... | Read more »
Gamebook: Pocket RPG (Games)
Gamebook: Pocket RPG 1.0.11 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.11 (iTunes) Description: Walk into the Land of Lanthir Lamath ruled by wicked skeletons and fight for your life in a thrilling adventure.... | Read more »
Kids Can Mix, Match, and Catch with Tata...
Tatadada MixMatch, by Tatadada Ltd, is a mobile version of the classic game of mix & match. The game uses brightly colored creatures to train your children's pattern matching skills and hand-eye coordination. It's aimed at children around age 5... | Read more »
The Trace: Murder Mystery Game (Games)
The Trace: Murder Mystery Game 1.2.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.2.0 (iTunes) Description: | Read more »
This Week at 148Apps: March 16-20, 2015
Spring Roars In At 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above... | Read more »

Price Scanner via MacPrices.net

Logitech Says MX Master Is Its Most Advanced...
Logitech’s new MX Master Wireless Mouse incorporates the best of Logitech’s many computer mouse innovations into a striking hand-sculpted design. The company claims that the MX Master creates a new... Read more
Save up to $300 on a new Mac, $30 on an iPad,...
Purchase a new Mac or iPad at The Apple Store for Education 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
Apple refurbished 2014 MacBook Airs available...
The Apple Store lowered prices on Apple Certified Refurbished 2014 MacBook Airs recently, with models now available starting at $679. An Apple one-year warranty is included with each MacBook, and... Read more
Mac Notebook Evolution; A Desktop Replacement...
More often than not right from the beginning, Apple’s Macs have tended to skew toward small. The original Macs were called “compacts,”, and notwithstanding a few exceptions like the honking Big Mac... Read more
13-inch 1.4GHz/128GB MacBook Air (Apple refur...
The Apple Store has Apple Certified Refurbished 2014 13″ 1.4GHz/128GB MacBook Airs available for $759 including free shipping plus Apple’s standard one-year warranty. Their price is $240 off original... Read more
YEP! Alternative Browser for iOS Now Supports...
Pfaeffikon, Switzerland based Power App AG has announced the release of an update to their Yep! Web Browser (v1.3.0) for iOS8 iPhone and iPad. Yep! hit the App Store shortly after the release of iOS... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for up to $250 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $... Read more
Clearance 13-inch Retina MacBook Pros availab...
B&H Photo has leftover 2014 13″ Retina MacBook Pros on sale for up to $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.6GHz/128GB Retina MacBook Pro: $1098... Read more
Clearance 2014 MacBook Airs on sale for up to...
B&H Photo has MacBook Airs on sale for up to $180 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 11″ 128GB MacBook Air: $789.99 110 off original MSRP - 11″ 256GB... Read more
Apple refurbished Time Capsules available for...
The Apple Store has certified refurbished Time Capsules available for $100 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $199, $100... Read more

Jobs Board

*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - D...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Systems Engineer - Pre Sales, Educat...
…is responsible for proactively providing technical expertise to drive sales of Apple solutions into assigned accounts. The SE architects, validates, and assists in Read more
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.