TweetFollow Us on Twitter

New PrGeneral

Volume Number: 13 (1997)
Issue Number: 6
Column Tag: develop

The New PrGeneral Version Opcode

by Ingrid Kelly

For the past 12 years, printer driver developers have used the print record's wDev field in the TPrStl data structure to store their device information. Specifically, they've consistently used the high-order byte of this field - commonly known as the wDev ID - to store the device code. Unfortunately, due to the design limitations of the print record and the wDev field, the Printing Manager allowed for a maximum of only 256 IDs. Surprisingly enough (ha ha), with the expansion of the printer market, we're running out of numbers! As a result, with LaserWriter driver version 8.4, we've added a PrGeneral opcode and new structures to the Printing Manager so that developers can work around this limitation.

Both printer driver and application developers need to add code to support this new information, but the changes are minimal. Accompanying this column on the MacTech Web site is a sample application, called PrGeneral Version, that shows you how to properly retrieve the new version information when your application is looking for the features of a particular printer driver.

The New PrGeneral Opcode:

kprversionop

LaserWriter driver version 8.4 introduced several new PrGeneral opcodes, including a new opcode for driver version information: kPrVersionOp. Using kPrVersionOp is now the recommended way for applications to find out the printer driver currently in use. Remember that for printer drivers that haven't updated to use this new PrGeneral opcode, your application needs to keep its wDev-checking code as well.

For more information on the extended print record opcodes introduced with LaserWriter version 8.4, read the Print Hints column "The All-New LaserWriter Driver Version 8.4" in develop Issue 27. There you'll find a table that lists all the other PrGeneral opcodes supported in Apple printer drivers. See the article "Meet PrGeneral, the Trap That Makes the Most of the Printing Manager" in develop Issue 3 for more information on PrGeneral.

What Printer Driver Developers Need to Know

From now on, Apple's Developer Support Center will assign all printer drivers a wDev ID of 255. If you have an old wDev ID number (which is less than 255), you should still use the number you were assigned so that you don't break any applications that vary their behavior based on your driver's wDev. In addition, you should implement the new kPrVersionOp opcode as described here so that new applications can take advantage of it with your driver.

Listing 1 shows the new opcode and structures that you'll need to implement in your PDEF 7 resource. You need to place your creator type in the driver.creator field of the TPrVersion structure. You should also place your version number in driver.release so that application developers know what version of the driver is available.

Listing 1. The new version opcode and structures

enum {
   ...
   kPrVersionOp = 22             // LaserWriter version 8.4 and later only
};

typedef struct {
   OSType     architecture;      // Architecture (for example, 'pwpc', 'm68k')
   OSType     creator;           // Driver's creator type (for example, 'AAPL')
   unsigned longrelease;         // Release number (for example, 0x8480)
   unsigned longinterfaces;      // Interfaces version (for example, 0x8480)
} TVersion;

typedef struct {
   short       iOpCode;          // Must be kPrVersionOp
   short       iError;           // For returning errors
   long        lReserved;        // Reserved, set to 0
   TVersion    driver;           // Driver information
   TVersion    reserved;         // Reserved, set to 0
} TPrVersion;

The release and interfaces fields have the same format as the first long in a 'vers' resource - that is, the following four 1-byte values: a major version number, a minor version number, a revision stage (development = 0x20, alpha = 0x40, beta = 0x60, and release = 0x80), and a prerelease version number.

That's all you'll need to do to support the new PrGeneral opcode in your driver - hard to believe, but true!

What Application Developers Need to Know

Although Apple doesn't recommend that application developers check the wDev field of the print record, many do. They assume that the wDev value means they can count on certain features being present in the printer. For instance, many developers assume that a wDev of 3 means the printer driver supports PostScript. In fact, it indicates only that the current printer uses the Apple LaserWriter driver. This leaves out the possibility that a user has a non-Apple PostScript printer driver with an ID of, say, 243.

Even though Apple doesn't recommend that application developers rely on the wDev field (or the new PrGeneral opcode, for that matter), if you're going to change application behavior based on the number or creator returned, at least do so properly so that your applications don't break with future releases of printer drivers. We recommend that you use the PrGeneral kPrVersionOp opcode, if available, to get the structure and then check the driver.creator and driver.release fields to determine the current printer driver and version (see Listing 1). You should also continue to support the old wDev method for printer drivers that have not yet updated to the new PrGeneral opcode. For your reference, the PrGeneral Version sample that accompanies this column shows how to properly retrieve the version and wDev information.

Go Forth and Print!

As you can see, the changes that printer driver and application developers need to make to support the new PrGeneral opcode are minimal. We've already adopted this new method with the LaserWriter version 8.4.x drivers. We hope you will, too!


WDEV Registration

Although from now on all printer drivers will be assigned a wDev ID of 255, we still request that you register your printer driver with Apple's Developer Support Center, to avoid creator type conflicts. To do so, register at http://www.devworld.apple.com/dev/wdev/. Here is the information you need to provide:

  • Company name and address
  • Contact name, phone number, and e-mail address
  • Make and model of device supported (for example, Apple LaserWriter 16/600)
  • Type of connection (for example, serial)
  • Creator type (for example, 'AAPL')

You'll receive confirmation of your registration within five to ten working days. If you have questions about wDev registration, write to devsupport@apple.com.


Related Reading

  • "Print Hints: The All-New LaserWriter Driver Version 8.4" by Dave Polaschek, develop Issue 27.
  • "Meet PrGeneral, the Trap that Makes the Most of the Printing Manager" by Pete "Luke" Alexander, develop Issue 3.

Ingrid Kelly (inge@apple.com) provides technical support for developers as a member of the Multimedia, Printing, Imaging, and Graphics group in Apple's Developer Technical Support. When she's not answering developer e-mails or trying to hold the record for most Technotes written in DTS, Ingrid can be found refilling her office candy bin, trying to come up with the ultimate chocolate chip cookie recipe, or attending Navy Blue Angels flight team demonstrations with her husband, Lance.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

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
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
OmniGraffle Pro 6.2.3 - Create diagrams,...
OmniGraffle Pro helps you draw beautiful diagrams, family trees, flow charts, org charts, layouts, and (mathematically speaking) any other directed or non-directed graphs. We've had people use... Read more
OmniFocus 2.2 - GTD task manager with iO...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more
Cocktail 8.4 - General maintenance and o...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
PDFKey Pro 4.3 - Edit and print password...
PDFKey Pro can unlock PDF documents protected for printing and copying when you've forgotten your password. It can now also protect your PDF files with a password to prevent unauthorized access and/... Read more
Kodi 15.0.beta1 - Powerful media center...
Kodi (was XBMC) is an award-winning free and open-source (GPL) software media player and entertainment hub that can be installed on Linux, OS X, Windows, iOS, and Android, featuring a 10-foot user... Read more
DiskCatalogMaker 6.4.12 - Catalog your d...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast. Finder-like intuitive look and feel. Super-fast search algorithm. Can compress catalog data... Read more
Macs Fan Control 1.3.0.0 - Monitor and c...
Macs Fan Control allows you to monitor and control almost any aspect of your computer's fans, with support for controlling fan speed, temperature sensors pane, menu-bar icon, and autostart with... 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 »
Desktop Dungeons is Now on the iPad Desp...
Desktop Dungeons has been a well-loved roguelike on PC for quite some time, and now it's finally available for the iPad! Just the iPad, though. Sorry iPhone users. [Read more] | Read more »
Moleskine Timepage – Calendar for iCloud...
Moleskine Timepage – Calendar for iCloud, Google & Exchange 1.0 Device: iOS iPhone Category: Productivity Price: $4.99, Version: 1.0 (iTunes) Description: The most elegant calendar for your pocket and wrist, Timepage is a... | Read more »
QuizUp Gets Social in its New Update
Plain Vanilla Corp has released a new and improved version of their popular trivia game, QuizUp. The app now emphasizes social play so you can challenge friends from all over the world. [Read more] | Read more »
The Deep (Games)
The Deep 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Swipe Controls Delve into the deep in this retro rogue-like! Swipe to move your diver around and keep away from the enemies as you... | Read more »
Sproggiwood (Games)
Sproggiwood 1.2.8 Device: iOS Universal Category: Games Price: $9.99, Version: 1.2.8 (iTunes) Description: Sproggiwood was developed for devices with at least 1GB of RAM. We recommend you only download Sproggiwood if your device... | Read more »
Battle of Gods: Ascension (Games)
Battle of Gods: Ascension 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: TURN-BASED TACTICAL COMBATFight tactical battles against the forces of Hades! In Battle of Gods: Ascension you play... | Read more »

Price Scanner via MacPrices.net

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
New 13-inch 2.9GHz Retina MacBook Pro on sale...
B&H Photo has the 13″ 2.9GHz/512GB Retina MacBook Pro on sale for $1699.99 including free shipping plus NY tax only. Their price is $100 off MSRP, and it’s the lowest price for this model from... Read more

Jobs Board

*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
Engineering Manager for *Apple* Maps on the...
…the Maps App Team get to take part in just about any new feature in Apple Maps, often contributing a majority of the feature work. In our day-to-day engineering work, we Read more
Senior Software Engineer - *Apple* SIM - Ap...
Changing the world is all in a day039s work at Apple . If you love innovation, here039s your chance to make a career of it. You039ll work hard. But the job comes with Read more
Lead *Apple* Solutions Consultant - Retail...
**Job Summary** Job Summary The Lead ASC is an Apple employee who serves as the Apple business manager and influencer in a hyper-business critical Reseller's store Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.