TweetFollow Us on Twitter

Sep 93 Think 10
Volume Number:9
Issue Number:9
Column Tag:Think Top 10

Think Top 10

By Thomas Emerson, THINK Technical Support, Symantec Corp.

This a monthly column written by Symantec's Technical Support Engineers intended to provide you with information on Symantec products. This month we cover some more commonly asked questions of Symantec’s developer technical support group.

Q. I want to write some assembly language for my C++ project, but I can't! The C++ compiler doesn't have an inline assembler and I can't figure out how to call my C++ functions from THINK C. Is there no hope?

A. You can call a C++ function from within an inline assembler block in the same way you would a C function: just JSR to the function. There is a slight complication though: the C++ language implements its type-safe linkage by “mangling” the name of functions and methods to contain the type information. So to call a C++ function from C, you need to use its mangled name. You can get the mangled name by turning on the “Generate MacsBug names” option in the Symantec C++ options dialog and disassembling the file containing the function whose mangled name you want. The mangled name will appear in a string at the end of the function. For example, assume that foo.cp contains the function:

void foo()
{
 for(int i=0;i<10;i++)
 ;
}

Disassembling foo.cp yields in part the following:

00000012: 261F              MOVE.L    (A7)+,D3
00000014: 4E75              RTS
00000016: 8766 6F6F 5F5F    DC.B      $80+$07, 'foo__Fv'
          4676           
0000001E: 0000              DC.W      0  ; size of literals
00000020

The mangled name for foo() is foo__Fv. So to call it from within the inline assembler we would write:

 asm {
 jsr    foo__Fv
 addq.l #4,sp
 };

remembering to prototype the function correctly, i.e.

 extern void foo__Fv(void);

and remember to use C++ calling conventions when passing arguments to the function. See pp. 73-75 of the C++ Compiler Guide for more details.

Q. On a related note, whenever I try to use the asm() statement in C++, I'm told that the function asm has no prototype. What's going on?

A. You will get this error if you have “ANSI conformance” option turned on in the Language Settings page of the Symantec C++ for Macintosh options dialog. As it says on page 40 of the C++ Compiler Guide , the keyword asm is not recognized. Turn this off and you will be all set.

Q. Can I build a code resource using Symantec C++ that uses C++ objects?

A. Sure, you can use C++ objects in code resources, though they cannot contain virtual methods. This is because the resource loader code does not support the 32-bit offsets used to build the vtables that are used for virtual method dispatch. We would recommend deriving all of your classes from PascalObject, which will support virtual methods and is an all around better way of doing it.

Q. It appears that your IOStreams library doesn't work when I turn on 68881 code generation. I built a version of IOStreams with the C++ compiler set to generate 881 instructions, but the simplest programs still don't work. What's wrong?

A. There are two things you need to do when using IOStreams with 68881 code generation. The library itself contains both C and C++ code, so you need to turn on 881 code generation for both the THINK C and Symantec C++ compilers. You also need to build a version of ANSI++ that uses 68881 code generation, since IOStreams makes calls to ANSI++ to do the dirty work.

Q. I’m a little confused on the difference between Stream.h and iostream.h. When should I use one and not the other?

A. The short and sweet answer is that you should ignore Stream.h completely and always use iostream.h. Stream.h contains the classes for the old Streams library described in the first edition of The C++ Programming Language. The header file is part of the Symantec C++ for Macintosh distribution, but the library itself was left out (though it is part of the MPW version, called SCOldstreamsIO.o and SCOldstreamsIO881.o). Unless you are porting old C++ source code that uses Stream.h you should use iostream.h instead.

Q. Since we're talking about streams here, I've found that when I create an fstream it shows up on my disk as a blank icon, and I can't open it. Is there any way to tell the compiler that I want a THINK C text file?

A. You can use a “feature” of the standard library to set the type and creator used when creating files. This works because the IOStreams library calls upon ANSI++ to do its dirty work, like creating and opening files. The file <stdio.h> declared two external globals, _ftype and _fcreator. These are used to set the initial type and creator for a file, so settings these to 'TEXT' and 'KAHL' respectively will solve your problem. The following code snippet should give you an idea of what to do:

#include <fstream.h>
#include <stdio.h>

void main()
{
 fstream fs;

 // set the type and creator for any streams we open
 _ftype = 'TEXT';
 _fcreator = 'KAHL';

 fs.open("foo.bar");
  
}

Q. I've heard about something called ToolServer. What is it and how do I use it?

A. ToolServer is a product developed by Apple that allows you to execute most MPW tools and scripts (the major exceptions being the editor and Projector commands.) Applications communicate with ToolServer by exchanging Apple events: in effect an MPW command line is sent to ToolServer, and the results of the command sent back to the calling application. The THINK Project Manager provides ToolServer support with this mechanism: if you press Command-Enter within any THINK editing window then the current selection (or the line the cursor is on if there isn't a selection) is sent to ToolServer. The TPM looks for an alias called “ToolServer” in the Tools folder, and launches this application if ToolServer isn't running.

ToolServer is distributed by Apple on the E.T.O. series (it first appeared in released form on E.T.O. #11) and in the MPW 3.3 distribution, both of which are available through APDA.

Q. Supposedly this is the THINK Top 10, yet there are only 8 questions, counting this one. What's the deal?

A. Well, perhaps we should have called this month's column the “THINK Top 010.” [read it in octal for those of you scratching your heads. - Ed.]

Thanks to Chris Prinos, Kevin Irlen, and Phil Shapiro for their contributions to the answers this month.

 
AAPL
$97.67
Apple Inc.
+0.64
MSFT
$44.50
Microsoft Corpora
+0.10
GOOG
$589.02
Google Inc.
-4.33

MacTech Search:
Community Search:

Software Updates via MacUpdate

TinkerTool 5.3 - Expanded preference set...
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the... Read more
Audio Hijack Pro 2.11.0 - Record and enh...
Audio Hijack Pro drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio with Audio Hijack... Read more
Intermission 1.1.1 - Pause and rewind li...
Intermission allows you to pause and rewind live audio from any application on your Mac. Intermission will buffer up to 3 hours of audio, allowing users to skip through any assortment of audio... Read more
Autopano Giga 3.6 - Stitch multiple imag...
Autopano Giga allows you to stitch 2, 20, or 2,000 images. Version 3.0 integrates impressive new features that will definitely make you adopt Autopano Pro or Autopano Giga: Choose between 9... Read more
Airfoil 4.8.7 - Send audio from any app...
Airfoil allows you to send any audio to AirPort Express units, Apple TVs, and even other Macs and PCs, all in sync! It's your audio - everywhere. With Airfoil you can take audio from any... Read more
Microsoft Remote Desktop 8.0.8 - Connect...
With Microsoft Remote Desktop, you can connect to a remote PC and your work resources from almost anywhere. Experience the power of Windows with RemoteFX in a Remote Desktop client designed to help... Read more
xACT 2.30 - Audio compression toolkit. (...
xACT stands for X Aaudio Compression Toolkit, an application that encodes and decodes FLAC, SHN, Monkey’s Audio, TTA, Wavpack, and Apple Lossless files. It also can encode these formats to MP3, AAC... Read more
Firefox 31.0 - Fast, safe Web browser. (...
Firefox for Mac offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals... Read more
Little Snitch 3.3.3 - Alerts you to outg...
Little Snitch gives you control over your private outgoing data. Track background activityAs soon as your computer connects to the Internet, applications often have permission to send any... Read more
Thunderbird 31.0 - Email client from Moz...
As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements... Read more

Latest Forum Discussions

See All

Jacob Jones and the Bigfoot Mystery : Ep...
Jacob Jones and the Bigfoot Mystery : Episode 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Jacob Jones is back in Episode 2 of one of Apples 'Best of 2013' games and an App Store... | Read more »
New Trailer For Outcast Odyssey, A New K...
New Trailer For Outcast Odyssey, A New Kind of Card Battler Posted by Jennifer Allen on July 25th, 2014 [ permalink ] Out this Fall is a new kind of card battle game: Outcast Odyssey. | Read more »
Garfield: Survival of the Fattest Coming...
Garfield: Survival of the Fattest Coming to iOS this Fall Posted by Jennifer Allen on July 25th, 2014 [ permalink ] Who loves lasagna? Me. Also everyone’s favorite grumpy fat cat, Garfield. | Read more »
Happy Flock Review
Happy Flock Review By Andrew Fisher on July 25th, 2014 Our Rating: :: HERD IT ALL BEFOREUniversal App - Designed for iPhone and iPad Underneath the gloss of Happy Flock’s visuals is a game of very little substance. It’s cute, but... | Read more »
Square Register Updates Adds Offline Pay...
Square Register Updates Adds Offline Payments Posted by Ellis Spice on July 25th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Looking For Group – Hearthstone’s Curse...
For the first time since its release (which has thankfully been a much shorter window for iPad players than their PC counterparts), Blizzard’s wildly successful Hearthstone: Heroes of Warcraft CCG is sporting some brand new content: the single... | Read more »
Poptile Review
Poptile Review By Jennifer Allen on July 25th, 2014 Our Rating: :: SIMPLY FUNUniversal App - Designed for iPhone and iPad Simple yet a little bit glorious, Poptile is a satisfying entertaining puzzle game with oodles of the ‘one... | Read more »
Modern Combat 5: Blackout Review
Modern Combat 5: Blackout Review By Brittany Vincent on July 25th, 2014 Our Rating: :: LESS QQ, MORE PEW PEWUniversal App - Designed for iPhone and iPad The fifth entry into the blockbuster Modern Combat series is what mobile... | Read more »
Watch and Share Mobile Gameplay Videos W...
Watch and Share Mobile Gameplay Videos With Kamcord Posted by Jennifer Allen on July 25th, 2014 [ permalink ] iPhone App - Designed for the iPhone, compatible with the iPad | Read more »
THE KING OF FIGHTERS '98 (Games)
THE KING OF FIGHTERS '98 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: Series’ masterpiece “KOF ’98” finally joins the battle on iPhone! FEATURES:■ The best game balance in the “KOF”... | Read more »

Price Scanner via MacPrices.net

iMacs on sale for $150 off MSRP, $250 off for...
Best Buy has iMacs on sale for up to $160 off MSRP for a limited time. Choose free home shipping or free instant local store pickup (if available). Prices are valid for online orders only, in-store... Read more
Mac minis on sale for $100 off MSRP, starting...
Best Buy has Mac minis on sale for $100 off MSRP. Choose free shipping or free instant local store pickup. Prices are for online orders only, in-store prices may vary: 2.5GHz Mac mini: $499.99 2.3GHz... Read more
Global Tablet Market Grows 11% in Q2/14 Notwi...
Worldwide tablet sales grew 11.0 percent year over year in the second quarter of 2014, with shipments reaching 49.3 million units according to preliminary data from the International Data Corporation... Read more
New iPhone 6 Models to Have Staggered Release...
Digitimes’ Cage Chao and Steve Shen report that according to unnamed sources in Apple’s upstream iPhone supply chain, the new 5.5-inch iPhone will be released several months later than the new 4.7-... Read more
New iOS App Helps People Feel Good About thei...
Mobile shoppers looking for big savings at their favorite stores can turn to the Goodshop app, a new iOS app with the latest coupons and deals at more than 5,000 online stores. In addition to being a... Read more
Save on 5th generation refurbished iPod touch...
The Apple Store has Apple Certified Refurbished 5th generation iPod touches available starting at $149. Apple’s one-year warranty is included with each model, and shipping is free. Many, but not all... Read more
What Should Apple’s Next MacBook Priority Be;...
Stabley Times’ Phil Moore says that after expanding its iMac lineup with a new low end model, Apple’s next Mac hardware decision will be how it wants to approach expanding its MacBook lineup as well... Read more
ArtRage For iPhone Painting App Free During C...
ArtRage for iPhone is currently being offered for free (regularly $1.99) during Comic-Con San Diego #SDCC, July 24-27, in celebration of the upcoming ArtRage 4.5 and other 64-bit versions of the... Read more
With The Apple/IBM Alliance, Is The iPad Now...
Almost since the iPad was rolled out in 2010, and especially after Apple made a 128 GB storage configuration available in 2012, there’s been debate over whether the iPad is a serious tool for... Read more
MacBook Airs on sale starting at $799, free s...
B&H Photo has the new 2014 MacBook Airs on sale for up to $100 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels... Read more

Jobs Board

*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Sr. Project Manager for *Apple* Campus 2 -...
…the design and construction of one building or building components of the New Apple Campus located in Cupertino, CA. They will provide project management oversight for Read more
WW Sales Program Manager, *Apple* Online St...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.