TweetFollow Us on Twitter

Aug 95 Tips
Volume Number:11
Issue Number:8
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

While developing an init that installs a system wide patch I needed a simple way to enable or disable it (forcing it to call the original patch) from the controlling application.

I found that the Gestalt manager could come in useful. In fact the procedure that installs a new selector, used in this case to check for the existence of the init, requires you to specify a response function which gets executed whenever the new selector is called. Being the function itself is part of the init, it is able to change the value of a status variable and return its state: assuming that the variable is a boolean. With two gestalt calls (max) it is possible to change the patch status. Follow some code fragments:

// global constants
#define kPatchSelector    'Test'   // must be OSType
#define kPatchNotPresent  0
#define kPatchPresent1

// INIT FRAGMENT
// INIT globals
Boolean gUsePatch = 3Dfalse;
SelectorFunctionUPPgGestaltSelectorFunction;

// install new gestalt selector
OSErr InstallGestalt(void) 
{
 OSErr  error;

 long   oldA4;
 oldA4 =3D SetUpA4();

 gGestaltSelectorFunction = 
 3DNewSelectorFunctionProc(PatchGestalt);
 error = 3DNewGestalt(kPatchSelector, 
 gGestaltSelectorFunction);

 RestoreA4(oldA4);
 return error;
}

//gestalt response function
pascal OSErr PatchGestalt(OSType gestaltSelector,long* 
 gestaltResponse)
{
    // use the global data in _this file_
 long oldA4;
 oldA4 = 3D SetUpA4();

 if (gUsePatch) { 
 *gestaltResponse = 3DkPatchNotPresent;
 gUsePatch = 3Dfalse;
 }
 else {
 *gestaltResponse = 3DkPatchPresent;
 gUsePatch=3Dtrue;
 }

 // restore the a4 world
 RestoreA4(oldA4);
 
 return noErr;
}
// APPLICATION FRAGMENT
OSErr TogglePatch(Boolean engage)
{
 OSErr  error=3DnoErr;
 long   gestaltFeature=3D0;

    //this call switches the = patch status
 error = 3DGestalt(kPatchSelector,&gestaltFeature);

 if (engage) {
    // was = already engaged; turn it back on
 if ((error = 3D = 3DnoErr) &&     
 (gestaltFeature = 3D = 3DkPatchNotPresent))
 error = 3DGestalt(kPatchSelector,&gestaltFeature);
 }
 else {
    // was = already disabled; turn it back off
 if ((error=3D=3DnoErr) && 
 (gestaltFeature=3D=3DkPatchPresent))
 error=3DGestalt(kPatchSelector,&gestaltFeature);
 }

 return error;
}

- Luigi Belverato
Milano, Italy

HandleMenuChoice

This tip may be a little obvious, I caught it right away, but some people may not have noticed the problem yet. Some people may have coded around it to begin with, but I didn't.

System 7.5 was the first time I saw the "Apple Menu Options" control panel. It is an extremely useful tool, I love it and use it constantly. But, there may be a slight difference in the way your application needs to handle menu highliting now that this control panel exists.

Here is the assumption I had been making for a long time: When the user selects a menu item, MenuSelect (and MenuKey) leave the menu title hilited. The application performs the indicated action and then unhilites the menu title. When no menu item is selected by the user (MenuSelect or MenuKey return 0L), the menu titles are not left hilited after the call.

The Apple Menu Options control panel is an exception. A menu selection in a submenu of the apple menu will leave the apple menu hilited, but MenuSelect will return 0L.

In the event handling code I have calls like this:

HandleMenuChoice( MenuSelect( event->where ) );
HandleMenuChoice( MenuKey( event->message & charCodeMask ) );

HandleMenuChoice looked like this:

void  HandleMenuChoice( long menuChoice )
{
 short  menu;
 short  item;
 
 if ( menuChoice != 0L ) {
 menu = HiWord( menuChoice );
 item = LoWord( menuChoice );
 
 switch ( menu ) {
 case mApple:
 HandleAppleChoice( item );
 break;
 case mFile:
 HandleFileChoice( item );
 break;
    // Other menus go here.
 }
 HiliteMenu( 0 );
 }
}

With this code, if the user selected an item in a submenu of the apple menu, the system will switch to the Finder and open the selected item (thanks to Apple Menu Options). When you switch back to your application, the apple menu will still be hilited (even if you call DrawMenuBar on the switch).

The work around is simple, call HiliteMenu( 0 ) even if MenuSelect returns 0L.

HandleMenuChoice should look like this:

void  HandleMenuChoice( long menuChoice )
{
 short  menu;
 short  item;
 
 if ( menuChoice != 0L ) {
 menu = HiWord( menuChoice );
 item = LoWord( menuChoice );
 
 switch ( menu ) {
 case mApple:
 HandleAppleChoice( item );
 break;
 case mFile:
 HandleFileChoice( item );
 break;
 // Other menus
 }
 // HiliteMenu( 0 ) was here
 }
 HiliteMenu( 0 );  // moved it to here
}

Your code may not look anything like this, but the idea is to call HiliteMenu( 0 ) even if MenuSelect returns 0L.

- Don Bresee
Los Angeles, CA

The Lost Paper

True story: I was once typing in some text in a word processor, when the computer suddenly crashed on me. I didn’t save a copy on to the hard-disk yet. I had to restart the computer and type it all over again. “But wait, the paper is still in the machine” I thought to myself. You see, when you restart all of the computer’s memory doesn’t get cleared, it just stays to what it was until it gets replaced with other information (usually, much like the behavior of a hard-disk). I had one thing going for me, I had MacsBug installed. Here are the steps I took to recover the paper:

First, I logged all of the work I was doing in MacsBug to a file. I did this using the “log” command. All you need to give the command is the name of the new file to log to. I named it “MyPaper” Good, now all of my MacsBug session will be on the hard-disk, so I can open it up with a normal text editor when I’m done.

Next, I needed to find where in memory my paper was. I did this using the “f” command. The first two parameters for this command is the range in memory in which you want MacsBug to search through. I wanted to search through all of my memory, which is 8 megs, so I typed in: “f 0 (400 * 400 * 8) “any string””. Where 0 is the beginning of memory and 8 megs is the top of it. The last parameter is the search string, balanced between two single quotes. I wanted to pick a distinct string, otherwise I would have hit other parts of memory that had it too, making the process take longer. I knew the word aardvark was mentioned in my paper, so I typed in this for the find command:

f 0 (400 * 400 * 8) “aardvark”

MacsBug then started searching for me. It came up with a small memory dump of something with the word arrdvark in it, but the words after it were not mine. (Which meant that I found another part of memory instead of my paper.) I then hit return to tell MacsBug to keep on searching. It then came up with a dump from my paper:

Searching for “aardvark” from 00000000 to 007FFFFF
  00358200  6161 7264 7661 726B  8000 0000 0000 002C  aardvark answer,

Which was very good news indeed! This told me that the string “aardvark answer” could be found at address 00358200. (I got this address from the leftmost number given.)

Now that I knew where it was, the rest my task would be easy. I used MacsBug’s display memory ASCII command to show me what came after it, by typing in: “dma 00358200”. (You might not have this command, in which case you’ll have to use plain old dm, instead of dma.) I hit return until my paper was done being displayed.

Note: You can subract a number from the address to see what was before it. For instance, subracting #200 from an address will give you the address of the first byte of the 200 byte block before it.

I then typed in “log” again, which closed my log. I finally went out of MacsBug and opened the log file with SimpleText. Remember, the log had my whole session, not just the paper, so I had to delete the addresses and such from it, (which really isn’t that hard to do, if you know how to use your mouse and your delete key efficiently). The paper was saved.

Warning: In your search you might stumble upon MacsBug’s very own memory, with its own copy of your search string. To get out of this recursive loop, start the search over again with the base search address being outside of MacsBug’s memory.

- Macneil Shonle
Yarmouth Maine, MacneilS@aol.com

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

pwSafe 4.0.1 - Secure password managemen...
pwSafe provides simple and secure password management across devices and computers. pwSafe uses iCloud to keep your password databases backed-up and synced between Macs and iOS devices. It is... Read more
WALTR 1.5.4 - Drag-and-drop any media fi...
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
Audio Hijack 3.1 - Record and enhance au...
Audio Hijack (was 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... Read more
PopChar 7.1 - Floating window shows avai...
We're also selling a 5-license family pack for only $25.99! PopChar helps you get the most out of your font collection. With its crystal-clear interface, PopChar X provides a frustration-free way to... Read more
BBEdit 11.1.1 - Powerful text and HTML e...
BBEdit is the leading professional HTML and text editor for the Mac. Specifically crafted in response to the needs of Web authors and software developers, this award-winning product provides a... Read more
Picasa 3.9.139 - Organize, edit, and sha...
Picasa and Picasa Web Albums allows you to organize, edit, and upload your photos to the Web from your computer in quick, simple steps. Arrange your photos into folders and albums and erase their... Read more
Mac DVDRipper Pro 5.0.5 - Copy, backup,...
Mac DVDRipper Pro is the DVD backup solution that lets you protect your DVDs from scratches, save your batteries by reading your movies from your hard disk, manage your collection with just a few... Read more
NetShade 6.2 - Browse privately using an...
This promotion is for NetShade and 1 year of Proxy and VPN services NetShade is an anonymous proxy and VPN app+service for Mac. Unblock your Internet through NetShade's high-speed proxy and VPN... Read more
CrossOver 14.1.3 - Run Windows apps on y...
CrossOver can get your Windows productivity applications and PC games up and running on your Mac quickly and easily. CrossOver runs the Windows software that you need on Mac at home, in the office,... Read more
Little Snitch 3.5.3 - Alerts you about o...
Little Snitch gives you control over your private outgoing data. Track background activity As soon as your computer connects to the Internet, applications often have permission to send any... Read more

Block Fortress has a Big New Update for...
Block Fortress is a survival-style game that's as fun as it is blocky. It's also just gotten a rather sizeable update that adds a lot more cool stuff. [Read more] | Read more »
Simple and Surreal Star Base Sim rymdkap...
I really like rymdkapsel. Not just because I'm a sucker for games that are cleverly simple or highly stylisitc, but because it's fun and challenging. Actually it's extremely challenging, which is why I was excited to learn that it's getting a couple... | Read more »
Check out the anticipated Angel Stone in...
Fincon has finally revealed Angel Stone in action in the first ever official gameplay trailer for the anticipated hack and slasher. Angel Stone is set in a post-apocalyptic world in which humanity is in danger of being wiped out by the demonic... | Read more »
Moleskine Timepage is an All-New Calenda...
Moleskine Timepage is a bit of a departure for the notebook manufacturer (since it has little to do with notebooks), but it certainly carries their simple and elegant style quite well. [Read more] | Read more »
Jog on Over and Check Out the New Runtas...
Runtastic has put out a fair number of apps to help you sleep, track excercise, and train various parts of your body. Now it's time for your legs to have their own time in the spotlight with Runtastic Leg Trainer. [Read more] | Read more »
It's Lights Out in the Upcoming Pla...
Ember’s Journey is a stark puzzle platformer with a twist: the entire game is played in darkness. The only light you can see by is the one emanating from your own character. [Read more] | Read more »
MooVee - Your Movies Guru (Entertainmen...
MooVee - Your Movies Guru 1.0 Device: iOS iPhone Category: Entertainment Price: $1.99, Version: 1.0 (iTunes) Description: MooVee helps you effortlessly manage your movies, on your iPhone. | Read more »
Geometry Wars 3: Dimensions (Games)
Geometry Wars 3: Dimensions 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: Enjoy the next chapter in the award-winning Geometry Wars franchise and enjoy stunning, console-quality... | Read more »
CHAOS RINGS Ⅲ (Games)
CHAOS RINGS Ⅲ 1.0.0 Device: iOS Universal Category: Games Price: $19.99, Version: 1.0.0 (iTunes) Description: The newest addition to the popular smartphone RPG series is finally here! ・CHAOS RINGS Overview | Read more »
The Popular Insight Series of Travel Gui...
Getting around in a country when you can't understand the primary language can be tough. Fortunately there are several options available to help wold travellers with the important stuff like giving directions to a cab driver or asking where the... | Read more »

Price Scanner via MacPrices.net

Top Markets Saturation To Slow Global Smartph...
According to a new mobile phone forecast from the International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker, smartphone shipments are expected to grow 11.3% in 2015 — down from 27... Read more
Apple refurbished 2014 13-inch Retina MacBook...
The Apple Store has Apple Certified Refurbished 2014 13″ Retina MacBook Pros available for up to $400 off original MSRP, starting at $979. An Apple one-year warranty is included with each model, and... Read more
What Would the ideal Apple Productivity Platf...
For the past four years I’ve kept a foot in both the Mac and iPad camps respectively. my daily computing hours divided about 50/50 between the two devices with remarkable consistency. However, there’... Read more
PageMeUp 1.2.1 Ten Dollar Page Layout Applica...
Paris, France-based Softobe, an OS X software development company, has announced that their PageMeUp v. 1.2.1, is available on the Mac App Store for $9.99. The license can be installed on up to 5... Read more
Eight New Products For USB Type-C Application...
Fresco Logic, specialists in advanced connectivity technologies and ICs, has introduced two new product families targeting the Type-C connector recently introduced across a number of consumer... Read more
Scripps National Spelling Bee Launches Buzzwo...
Scripps National Spelling Bee fans can monitor the action at the 2015 Spelling Bee with the new Buzzworthy app for iOS, Android and Windows mobile devices. The free Buzzworthy app provides friendly... Read more
13-inch 2.5GHz MacBook Pro on sale for $120 o...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $979 including free shipping plus NY sales tax only. Their price is $120 off MSRP, and it’s the lowest price for this model (except for Apple’... Read more
27-inch 3.3GHz 5K iMac on sale for $1899, $10...
B&H Photo has the new 27″ 3.3GHz 5K iMac on sale for $1899.99 including free shipping plus NY tax only. Their price is $100 off MSRP. Read more
Save up to $50 on iPad Air 2, NY tax only, fr...
B&H Photo has iPad Air 2s on sale for up to $50 off MSRP including free shipping plus NY sales tax only: - 16GB iPad Air 2 WiFi: $469 $30 off - 64GB iPad Air 2 WiFi: $549.99 $50 off - 128GB iPad... Read more
Updated Mac Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Program Manager, *Apple* Community Support...
**Job Summary** Apple Support Communities ( discussions. apple .com) helps customers get the most from their Apple products and services by providing access to Read more
Senior Data Scientist, *Apple* Retail - Onl...
**Job Summary** Apple Retail - Online sells Apple products to customers around the world. In addition to selling Apple products with unique services such as iPad Read more
*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* Watch SW Application Project Manager...
**Job Summary** The Apple Watch software team is looking for an Application Engineering Project Manager to work on new projects for Apple . The successful candidate Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.