TweetFollow Us on Twitter

Feb 95 Top 10
Volume Number:11
Issue Number:2
Column Tag:Think Top 10

Think Top 10

This monthly column, written by Symantec’s Technical Support Engineers, aims to provide you with technical information based on the use of Symantec products.

By Mark B. Baldwin and Steve Howard, Symantec Technical Support

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

Q. Why do I get bus errors when I create a CStyleText object by using the constructor with arguments?

A. In the process of upgrading the TCL, constructors with arguments were added to the classes. In this case, constructors with arguments do not create a new handle to a TERec, the macTE data member of the CStyleText object. To work around this, call the constructor with no arguments and call the IStyleTextX() method.

Q. I am having trouble using sizeof() with printf(). For example:

printf("char size is %d.", sizeof(char));

outputs "char size is 0." Why do I get the wrong result?

A. The output is wrong because the return value of the sizeof() function is a size_t (an unsigned long). Use an %ld rather than a %d as a format specifier. Thus, the correct syntax is

"printf ("The size of a char is %ld.", sizeof(char));" 

Q. How can I avoid problems deleting heap objects whose references are on the stack when using exception handling? The pointer (which is on the stack) to the object becomes invalid when the stack unwinds and only the destructors for automatic objects are guaranteed to be called when an exception is thrown.

A. To handle this, declare pointers as volatile. Last month we explained why you should use the volatile type. Below is a practical example. Use volatile file pointers so that stack unwinding does not reset the value of the pointer (prohibiting the file from being closed).

  funClass * volatile funClassPtr;    // Syntax for volatile declaration 
  funClassPtr = NULL;         // Pointer to NULL guarantees delete as safe.
  int myInt = 1;                      // Watch in debugger to see
                                      //   the stack unwind.
  try_ {
    funClassPtr = TCL_NEW(funClass, ());//macro for new operator
    myInt = 2;                          //put new value on stack
    Failure (2, 100);                   // Force exception 
  } 
  catch_all_() {                      //catch block
    
  delete funClassPtr;                 //this calls destructor.
     
     // myInt is reset to 1, delete removes the object from the  heap 
  }
  end_try_                            //end of try block

Q. How can I use exception handling without using the Think Class Library?

A. To use exception handling without the Think Class Library, include BRLib and Exceptions.cp in your project. Also, compile with the directive #define NO_TCL

The four macros used to make exception handling work correctly are:

  AUTO_DESTRUCT_OBJECT
  TCL_NEW
  TCL_END_CONSTRUCTOR
  TCL_START_DESTRUCTOR

The macro AUTO_DESTRUCT_OBJECT will guarantee that the destructor is called for an automatic object on the stack. A destructor will only work on a completely constructed object. TCL_END_CONSTRUCTOR helps the compiler to determine the complete construction of an object.

Here’s an example that shows how the macros are used.

class funClass TCL_AUTO_DESTRUCT_OBJECT //macro in class header  
{ 
public:
    funClass()  {                       // no arg constructor 
    cout<< "In constructor."<<endl;
    char * myStr = new char[64];        // allocate memory 
    TCL_END_CONSTRUCTOR                 // End of the constructor
    }
    virtual ~funClass() {               // virtual destructor 
    TCL_START_DESTRUCTOR                // Beginning of the destructor 
    cout<< "In destructor."<<endl;
    delete [] myStr;                    // deallocate memory 
    } 
};

Q. Where can I get the Quickdraw GX headers?

A. APDA has a Quickdraw GX Developer’s Kit which contains a CD with the electronic versions of Inside Macintosh for GX, headers, required system software components, and excellent examples which are compilable under THINK C or Symantec C++. For ordering information, call (800) 282-2732. [If all you need is the header files, check out the MacTech Magazine online sites. See page 2 for details - Ed stb]

Q. When I build an application with the TCL, the application does not seem to be scriptable. How can I make it scriptable?

A. The default flags for the SIZE Resource of the application are set to not receive Background NULL Events. Make sure that the flags for your application have this bit turned on.

Q. I have a program that I’m converting from DOS and would like to be able to draw some simple graphics to the console window. How can I do that?

A. Don’t do it. If you draw to the console window, you will not receive update events. However, if you just can’t help yourself from going down this path, here is how to do it.

 #include <iostream.h>
    
 WindowPtr myWindow;         // To be used for the console window.
     
 void main (void)    {    
   cout << " ";                //A simple way to show the console.
   myWindow = FrontWindow();   //Get a pointer to the console.
   SetPort(myWindow);          //Set the port for drawing.
   PenNormal();                //Set the pen for drawing.
   LineTo(100,47);             //Draw a line.     
 }

Q. If I am mixing C and C++ code, should I turn on the option to use Native Floating Point format?

A. Yes. Symantec’s C++ compiler is using the Native Floating Point format. To make sure that your floating point calculations give you the expected results, turn on Use Native Floating Point in the options for the C compiler.

Q. Will Symantec be updating the THINK Reference Databases?

A. Yes. THINK Reference is undergoing a massive overhaul. It will be updated for the Universal Headers and the Think Class Library, and will include new databases for C++ Error Messages. As before, references will be hyperlinked for easy access to information.

Special thanks to: Craig Conner, Colen Garoutte-Carson, Rick Hartmann, Michael Hopkins, Scott Morison, Celso Barriga, Kevin Irlen, Yuen Li, and Chris Prinos.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Mojave Cache Cleaner 12.0.6 - Clear cach...
Mojave Cache Cleaner is an award-winning general purpose tool for macOS X. SCC makes system maintenance simple with an easy point-and-click interface to many macOS X functions. Novice and expert... Read more
BetterTouchTool 3.161 - Customize multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom)... Read more
macOS Mojave 10.14.6 - The latest OS fro...
macOS Mojave delivers new features inspired by its most powerful users but designed for everyone. Stay focused on your work using Dark Mode. Organize your desktop using Stacks. Experience three new... Read more
CleanMyMac X 4.4.5 - Delete files that w...
CleanMyMac makes space for the things you love. Sporting a range of ingenious new features, CleanMyMac lets you safely and intelligently scan and clean your entire system, delete large, unused files... Read more
Sketch 56 - Design app for UX/UI for iOS...
Sketch is an innovative and fresh look at vector drawing. Its intentionally minimalist design is based upon a drawing space of unlimited size and layers, free of palettes, panels, menus, windows, and... Read more
VueScan 9.6.46 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
XMind ZEN 9.2.1 - Mind mapping and proje...
XMind ZEN is a mind-mapping tool based off of the same open-source project as XMind Pro. It supports the same map structures and 100% compatible with XMind 8. It has new themes, some with more muted... Read more
XMind Pro 8 Update 8 - Popular mind mapp...
XMind Pro claims to be the most popular mind-mapping tool on the planet. You can use it to work through an individual brainstorming session and it will record and collect inspirations as you go. It... Read more
Apple Safari 12.1.2 - Apple's Web b...
Apple Safari is Apple's web browser that comes bundled with the most recent macOS. Safari is faster and more energy efficient than other browsers, so sites are more responsive and your notebook... Read more
Transmit 5.5.2 - Excellent FTP/SFTP clie...
Transmit is an excellent FTP (file transfer protocol), SFTP, S3 (Amazon.com file hosting) and iDisk/WebDAV client that allows you to upload, download, and delete files over the internet. With the... Read more

Latest Forum Discussions

See All

Void Tyrant guide - Tips and tricks for...
Void Tyrant continues to get a lot of play in these parts. Probably because the game is just so deep and varied. The next stop on our guide series for Void Tyrant is class-specific guides. First up is the Knight, as it’s the first class anyone has... | Read more »
Summon beasts and battle evil in epic re...
Imagine a tale of conlict between factions of good and evil, where rogueish heroes summon beasts to aid them in them in warfare and courageously battle dragons over fields of scorched earth and brimstone - that's exactly the essence of epic fantasy... | Read more »
Upcoming visual novel Arranged shines a...
If you’re in the market for a new type of visual novel designed to inform and make you think deeply about its subject matter, then Arranged by Kabuk Games could be exactly what you’re looking for. It’s a wholly unique take on marital traditions in... | Read more »
TEPPEN guide - The three best decks in T...
TEPPEN’s unique take on the collectible card game genre is exciting. It’s just over a week old, but that isn’t stopping lots of folks from speculating about the long-term viability of the game, as well as changes and additions that will happen over... | Read more »
Intergalactic puzzler Silly Memory serve...
Recently released matching puzzler Silly Memory is helping its fans with their intergalactic journeys this month with some very special offers on in-app purchases. In case you missed it, Silly Memory is the debut title of French based indie... | Read more »
TEPPEN guide - Tips and tricks for new p...
TEPPEN is a wild game that nobody asked for, but I’m sure glad it exists. Who would’ve thought that a CCG featuring Capcom characters could be so cool and weird? In case you’re not completely sure what TEPPEN is, make sure to check out our review... | Read more »
Dr. Mario World guide - Other games that...
We now live in a post-Dr. Mario World world, and I gotta say, things don’t feel too different. Nintendo continues to squirt out bad games on phones, causing all but the most stalwart fans of mobile games to question why they even bother... | Read more »
Strategy RPG Brown Dust introduces its b...
Epic turn-based RPG Brown Dust is set to turn 500 days old next week, and to celebrate, Neowiz has just unveiled its biggest and most exciting update yet, offering a host of new rewards, increased gacha rates, and a brand new feature that will... | Read more »
Dr. Mario World is yet another disappoin...
As soon as I booted up Dr. Mario World, I knew I wasn’t going to have fun with it. Nintendo’s record on phones thus far has been pretty spotty, with things trending downward as of late. [Read more] | Read more »
Retro Space Shooter P.3 is now available...
Shoot-em-ups tend to be a dime a dozen on the App Store, but every so often you come across one gem that aims to shake up the genre in a unique way. Developer Devjgame’s P.3 is the latest game seeking to do so this, working as a love letter to the... | Read more »

Price Scanner via MacPrices.net

New 2019 15″ MacBook Pros on sale for up to $...
Apple resellers B&H Photo and Amazon are offering the new 2019 15″ MacBook Pros for up to $250 off Apple’s MSRP including free shipping. These are the same MacBook Pros sold by Apple in its... Read more
New 2019 27″ 5K iMacs on sale for up to $150...
B&H Photo has the new 2019 27″ 5K iMacs on stock today and on sale for up to $150 off Apple’s MSRP. Shipping is free: – 27″ 3.0GHz 5K iMac: $1649 $150 off MSRP – 27″ 3.1GHz 5K iMac: $1849 $150... Read more
Clearance 2018 13″ 4-Core Touch Bar MacBook P...
Amazon has clearance 2018 13″ 2.3GHz 4-Core Touch Bar Apple MacBook Pros with 512GB SSDs available for $300 off original MSRP, only $1699. Shipping is free. Select Amazon as the seller, rather than a... Read more
Apple continues to offer the lowest prices on...
Apple has Certified Refurbished 2018 Mac minis available on their online store for $120-$170 off the cost of new models. Each mini comes with a new outer case plus a standard Apple one-year warranty... Read more
13″ 1.8GHz MacBook Air on sale again for only...
Amazon has the 2017 13″ 1.8GHz/128GB MacBook Air on sale today for only $749.99 shipped. That’s $250 off Apple’s original MSRP for this model and the cheapest MacBook Air available from any Apple... Read more
Apple’s $1489 clearance price on refurbished...
Apple has Certified Refurbished 2018 13″ 2.3GHz 4-Core Touch Bar MacBook Pros available starting at $1489. Apple’s one-year warranty is included, shipping is free, and each MacBook has a new outer... Read more
New 2019 13″ 2.4GHz 4-Core MacBook Pros on sa...
Apple resellers B&H Photo and Amazon are offering the new 2019 13″ 2.4GHz 4-Core Touch Bar MacBook Pros for $150 off Apple’s MSRP. These are the same MacBook Pros sold by Apple in its retail and... Read more
B&H drops prices another $50 on clearance...
B&H Photo has dropped prices on clearance 2018 13″ MacBook Airs by a further $50 with models now available for $250 off Apple’s original MSRP. Overnight shipping, or expedited shipping, is free... Read more
Find the best sales & lowest prices on Ap...
Our Apple award-winning price trackers are the best place to look for the best sales and lowest prices on Apple gear. Scan our price trackers for the latest information on sales, bundles, and... Read more
Apple has clearance 2018 13″ MacBook Airs now...
Apple has Certified Refurbished 2018 13″ MacBook Airs available starting at only $849. Each MacBook features a new outer case, comes with a standard Apple one-year warranty, and is shipped free. The... Read more

Jobs Board

Best Buy *Apple* Computing Master - Best Bu...
**711698BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Location Number:** 001387-New Braunfels-Store **Job Description:** **What does Read more
Best Buy *Apple* Computing Master - Best Bu...
**711495BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Location Number:** 000882-Waterfront-Store **Job Description:** The Read more
Best Buy *Apple* Computing Master - Best Bu...
**711597BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Location Number:** 000873-Colma CA-Store **Job Description:** **What does a Read more
Best Buy *Apple* Computing Master - Best Bu...
**711346BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Location Number:** 001095-Chesterfield-Store **Job Description:** Read more
Best Buy *Apple* Computing Master - Best Bu...
**704899BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Location Number:** 000135-Pleasant Hill-Store **Job Description:** **What does Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.