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

Capto 1.2.9 - $29.99
Capto (was Voila) is an easy-to-use app that takes capturing, recording, video and image editing to the next level. With an intelligent file manager and quick sharing options, Capto is perfect for... Read more
Opera 51.0.2830.40 - High-performance We...
Opera is a fast and secure browser trusted by millions of users. With the intuitive interface, Speed Dial and visual bookmarks for organizing favorite sites, news feature with fresh, relevant content... Read more
GarageSale 7.0.13 - Create outstanding e...
GarageSale is a slick, full-featured client application for the eBay online auction system. Create and manage your auctions with ease. With GarageSale, you can create, edit, track, and manage... Read more
1Password 6.8.7 - Powerful password mana...
1Password is a password manager that uniquely brings you both security and convenience. It is the only program that provides anti-phishing protection and goes beyond password management by adding Web... Read more
Evernote 7.0.1 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
MacUpdate Desktop 6.2.0 - $20.00
MacUpdate Desktop brings seamless 1-click app installs and version updates to your Mac. With a free MacUpdate account and MacUpdate Desktop 6, Mac users can now install almost any Mac app on... Read more
HoudahSpot 4.3.5 - Advanced file-search...
HoudahSpot is a versatile desktop search tool. Use HoudahSpot to locate hard-to-find files and keep frequently used files within reach. HoudahSpot will immediately feel familiar. It works just the... Read more
EtreCheck 4.0.4 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
WhatsApp 0.2.8361 - Desktop client for W...
WhatsApp is the desktop client for WhatsApp Messenger, a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for... Read more
iClock 4.2 - Customize your menubar cloc...
iClock is a menu-bar replacement for Apple's default clock but with 100x features. Have your Apple or Google calendar in the menubar. Have the day, date, and time in different fonts and colors in the... Read more

Latest Forum Discussions

See All

The best games like Florence
Florence is a great little game about relationships that we absolutely adored. The only problem with it is it's over a little too soon. If you want some other games with some emotional range like Florence, check out these suggestions: [Read more] | Read more »
Angry Birds Champions adds cash prizes t...
Collaborating with developer Rovio Entertainment, GSN Games has released a twist on the Angry Birds formula. Angry Birds Champions features the same bird-flinging gameplay, but now you can catapult Red and co for cash. | Read more »
Around the Empire: What have you missed...
148Apps is part of a family. A big family of sites that make sure you're always up to date with all the portable gaming news. Just like a real family, I guess. I don't know, my mum never told me anything about Candy Crush to be fair. [Read more] | Read more »
The Battle of Polytopia Guide - Tips for...
The addition of multiplayer to The Battle of Polytopia has catapulted the game from a fun enough time waster to a fully-fledged 4X experience on your phone. We've been playing quite a few matches over the past week or so, and we've put together a... | Read more »
All the best games on sale for iPhone an...
Hi there, and welcome to our round up of all the best games that are on sale for iOS at the moment. It's not a vintage week in terms of numbers, but I'm pretty sure that every single one of these is worth picking up if you haven't already played... | Read more »
Disc Drivin' 2 Guide - Tips for the...
We're all still playing quite a bit of Disc Drivin' 2 over here at 148Apps, and we've gotten pretty good at it. Now that we've spent some more time with the game and unlocked more powerups, check out some of these more advanced tips: | Read more »
Alto's Odyssey Guide - How to Tackl...
Alto’s Odyssey is a completely stunning and serene runner, but it can also be a bit tricky. Check out these to try and keep your cool while playing this endless runner: Don’t focus too much on tasks [Read more] | Read more »
Here's everything you need to know...
Alto's Odyssey is a really, really good game. If you don't believe me, you should definitely check out our review by clicking this link right here. It takes the ideas from the original Alto's Adventure, then subtly builds on them, creating... | Read more »
Alto's Odyssey (Games)
Alto's Odyssey 1.0.1 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.1 (iTunes) Description: Just beyond the horizon sits a majestic desert, vast and unexplored. Join Alto and his friends and set off on an endless... | Read more »
Vainglory 5v5: Everything you need to kn...
Vainglory just got bigger. [Read more] | Read more »

Price Scanner via MacPrices.net

Sale! Amazon offers 13″ 2.3GHz MacBook Pros f...
Amazon has 2017 13″ 2.3GHz Apple MacBook Pros on sale today for $151-$150 off MSRP, each including free shipping: – 13″ 2.3GHz/128GB Space Gray MacBook Pro (MPXQ2LL/A): $1148 $151 off MSRP – 13″ 2.... Read more
Apple AirPods in stock today for $159, free s...
Adorama reports stock of Apple AirPods today for $159 including free shipping, plus pay no sales tax outside of NY & NJ. See our Apple AirPod Price Tracker for the latest prices and stock status... Read more
Saturday Sale: Amazon offers 12″ 1.3GHz MacBo...
Amazon has Silver and Gold 2017 12″ 1.3GHz Retina MacBooks on sale for $250 off MSRP. Shipping is free: – 12″ 1.3GHz Silver MacBook: $1349.99 $250 off MSRP – 12″ 1.3GHz Gold MacBook: $1349.99 $250... Read more
Use your Apple Education discount and save up...
Purchase a new Mac using Apple’s Education discount, and take up to $400 off MSRP. All teachers, students, and staff of any educational institution with a .edu email address qualify for the discount... Read more
Apple Canada offers 2017 21″ and 27″ iMacs fo...
 Canadian shoppers can save up to $470 on the purchase of a 2017 current-generation 21″ or 27″ iMac with Certified Refurbished models at Apple Canada. Apple’s refurbished prices are the lowest... Read more
9″ iPads available online at Walmart for $50...
Walmart has 9.7″ Apple iPads on sale for $50 off MSRP for a limited time. Sale prices are for online orders only, in-store prices may vary: – 9″ 32GB iPad: $279.99 $50 off – 9″ 128GB iPad: $379.99 $... Read more
15″ Apple MacBook Pros, Certified Refurbished...
Save $360-$420 on the purchase of a 2017 15″ MacBook Pro with Certified Refurbished models at Apple. Apple’s refurbished prices are the lowest available for each model from any reseller. An standard... Read more
Amazon restocks MacBook Pros with models avai...
Amazon has restocked 15″ and 13″ Apple MacBook Pros with models on sale for up to $251 off MSRP. Shipping is free. Note that stock of some Macs may come and go (and some sell out quickly), so check... Read more
Lowest price of the year: 15″ 2.8GHz Apple Ma...
Amazon has the 2017 Space Gray 15″ 2.8GHz MacBook Pro on sale today for $251 off MSRP. Shipping is free: – 15″ 2.8GHz Touch Bar MacBook Pro Space Gray (MPTR2LL/A): $2148, $251 off MSRP Their price is... Read more
Apple restocks full line of Certified Refurbi...
Apple has restocked a full line of Apple Certified Refurbished 2017 13″ MacBook Pros for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more

Jobs Board

*Apple* Media Products Commerce Engineering...
# Apple Media Products Commerce Engineering Manager Job Number: 56207285 Santa Clara Valley, California, United States Posted: 26-Jan-2018 Weekly Hours: 40.00 **Job Read more
Digital Platforms Lead, Today at *Apple* -...
# Digital Platforms Lead, Today at Apple Job Number: 56178747 Santa Clara Valley, California, United States Posted: 23-Feb-2018 Weekly Hours: 40.00 **Job Summary** Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions - Apple,...
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* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.