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

coconutBattery 3.9.14 - Displays info ab...
With coconutBattery you're always aware of your current battery health. It shows you live information about your battery such as how often it was charged and how is the current maximum capacity in... Read more
Keynote 13.2 - Apple's presentation...
Easily create gorgeous presentations with the all-new Keynote, featuring powerful yet easy-to-use tools and dazzling effects that will make you a very hard act to follow. The Theme Chooser lets you... Read more
Apple Pages 13.2 - Apple's word pro...
Apple Pages is a powerful word processor that gives you everything you need to create documents that look beautiful. And read beautifully. It lets you work seamlessly between Mac and iOS devices, and... Read more
Numbers 13.2 - Apple's spreadsheet...
With Apple Numbers, sophisticated spreadsheets are just the start. The whole sheet is your canvas. Just add dramatic interactive charts, tables, and images that paint a revealing picture of your data... Read more
Ableton Live 11.3.11 - Record music usin...
Ableton Live lets you create and record music on your Mac. Use digital instruments, pre-recorded sounds, and sampled loops to arrange, produce, and perform your music like never before. Ableton Live... Read more
Affinity Photo 2.2.0 - Digital editing f...
Affinity Photo - redefines the boundaries for professional photo editing software for the Mac. With a meticulous focus on workflow it offers sophisticated tools for enhancing, editing and retouching... Read more
SpamSieve 3.0 - Robust spam filter for m...
SpamSieve is a robust spam filter for major email clients that uses powerful Bayesian spam filtering. SpamSieve understands what your spam looks like in order to block it all, but also learns what... Read more
WhatsApp 2.2338.12 - Desktop client for...
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
Fantastical 3.8.2 - Create calendar even...
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
iShowU Instant 1.4.14 - Full-featured sc...
iShowU Instant gives you real-time screen recording like you've never seen before! It is the fastest, most feature-filled real-time screen capture tool from shinywhitebox yet. All of the features you... Read more

Latest Forum Discussions

See All

The iPhone 15 Episode – The TouchArcade...
After a 3 week hiatus The TouchArcade Show returns with another action-packed episode! Well, maybe not so much “action-packed" as it is “packed with talk about the iPhone 15 Pro". Eli, being in a time zone 3 hours ahead of me, as well as being smart... | Read more »
TouchArcade Game of the Week: ‘DERE Veng...
Developer Appsir Games have been putting out genre-defying titles on mobile (and other platforms) for a number of years now, and this week marks the release of their magnum opus DERE Vengeance which has been many years in the making. In fact, if the... | Read more »
SwitchArcade Round-Up: Reviews Featuring...
Hello gentle readers, and welcome to the SwitchArcade Round-Up for September 22nd, 2023. I’ve had a good night’s sleep, and though my body aches down to the last bit of sinew and meat, I’m at least thinking straight again. We’ve got a lot to look at... | Read more »
TGS 2023: Level-5 Celebrates 25 Years Wi...
Back when I first started covering the Tokyo Game Show for TouchArcade, prolific RPG producer Level-5 could always be counted on for a fairly big booth with a blend of mobile and console games on offer. At recent shows, the company’s presence has... | Read more »
TGS 2023: ‘Final Fantasy’ & ‘Dragon...
Square Enix usually has one of the bigger, more attention-grabbing booths at the Tokyo Game Show, and this year was no different in that sense. The line-ups to play pretty much anything there were among the lengthiest of the show, and there were... | Read more »
Valve Says To Not Expect a Faster Steam...
With the big 20% off discount for the Steam Deck available to celebrate Steam’s 20th anniversary, Valve had a good presence at TGS 2023 with interviews and more. | Read more »
‘Honkai Impact 3rd Part 2’ Revealed at T...
At TGS 2023, HoYoverse had a big presence with new trailers for the usual suspects, but I didn’t expect a big announcement for Honkai Impact 3rd (Free). | Read more »
‘Junkworld’ Is Out Now As This Week’s Ne...
Epic post-apocalyptic tower-defense experience Junkworld () from Ironhide Games is out now on Apple Arcade worldwide. We’ve been covering it for a while now, and even through its soft launches before, but it has returned as an Apple Arcade... | Read more »
Motorsport legends NASCAR announce an up...
NASCAR often gets a bad reputation outside of America, but there is a certain charm to it with its close side-by-side action and its focus on pure speed, but it never managed to really massively break out internationally. Now, there's a chance... | Read more »
Skullgirls Mobile Version 6.0 Update Rel...
I’ve been covering Marie’s upcoming release from Hidden Variable in Skullgirls Mobile (Free) for a while now across the announcement, gameplay | Read more »

Price Scanner via MacPrices.net

New low price: 13″ M2 MacBook Pro for $1049,...
Amazon has the Space Gray 13″ MacBook Pro with an Apple M2 CPU and 256GB of storage in stock and on sale today for $250 off MSRP. Their price is the lowest we’ve seen for this configuration from any... Read more
Apple AirPods 2 with USB-C now in stock and o...
Amazon has Apple’s 2023 AirPods Pro with USB-C now in stock and on sale for $199.99 including free shipping. Their price is $50 off MSRP, and it’s currently the lowest price available for new AirPods... Read more
New low prices: Apple’s 15″ M2 MacBook Airs w...
Amazon has 15″ MacBook Airs with M2 CPUs and 512GB of storage in stock and on sale for $1249 shipped. That’s $250 off Apple’s MSRP, and it’s the lowest price available for these M2-powered MacBook... Read more
New low price: Clearance 16″ Apple MacBook Pr...
B&H Photo has clearance 16″ M1 Max MacBook Pros, 10-core CPU/32-core GPU/1TB SSD/Space Gray or Silver, in stock today for $2399 including free 1-2 day delivery to most US addresses. Their price... Read more
Switch to Red Pocket Mobile and get a new iPh...
Red Pocket Mobile has new Apple iPhone 15 and 15 Pro models on sale for $300 off MSRP when you switch and open up a new line of service. Red Pocket Mobile is a nationwide service using all the major... Read more
Apple continues to offer a $350 discount on 2...
Apple has Studio Display models available in their Certified Refurbished store for up to $350 off MSRP. Each display comes with Apple’s one-year warranty, with new glass and a case, and ships free.... Read more
Apple’s 16-inch MacBook Pros with M2 Pro CPUs...
Amazon is offering a $250 discount on new Apple 16-inch M2 Pro MacBook Pros for a limited time. Their prices are currently the lowest available for these models from any Apple retailer: – 16″ MacBook... Read more
Closeout Sale: Apple Watch Ultra with Green A...
Adorama haș the Apple Watch Ultra with a Green Alpine Loop on clearance sale for $699 including free shipping. Their price is $100 off original MSRP, and it’s the lowest price we’ve seen for an Apple... Read more
Use this promo code at Verizon to take $150 o...
Verizon is offering a $150 discount on cellular-capable Apple Watch Series 9 and Ultra 2 models for a limited time. Use code WATCH150 at checkout to take advantage of this offer. The fine print: “Up... Read more
New low price: Apple’s 10th generation iPads...
B&H Photo has the 10th generation 64GB WiFi iPad (Blue and Silver colors) in stock and on sale for $379 for a limited time. B&H’s price is $70 off Apple’s MSRP, and it’s the lowest price... Read more

Jobs Board

Optometrist- *Apple* Valley, CA- Target Opt...
Optometrist- Apple Valley, CA- Target Optical Date: Sep 23, 2023 Brand: Target Optical Location: Apple Valley, CA, US, 92308 **Requisition ID:** 796045 At Target Read more
Senior *Apple* iOS CNO Developer (Onsite) -...
…Offense and Defense Experts (CODEX) is in need of smart, motivated and self-driven Apple iOS CNO Developers to join our team to solve real-time cyber challenges. Read more
*Apple* Systems Administrator - JAMF - Activ...
…**Public Trust/Other Required:** None **Job Family:** Systems Administration **Skills:** Apple Platforms,Computer Servers,Jamf Pro **Experience:** 3 + years of Read more
Child Care Teacher - Glenda Drive/ *Apple* V...
Child Care Teacher - Glenda Drive/ Apple ValleyTeacher Share by Email Share on LinkedIn Share on Twitter Share on Facebook Apply Read more
Machine Operator 4 - *Apple* 2nd Shift - Bon...
Machine Operator 4 - Apple 2nd ShiftApply now " Apply now + Start apply with LinkedIn + Apply Now Start + Please wait Date:Sep 22, 2023 Location: Swedesboro, NJ, US, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.