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

Latest Forum Discussions

See All

Soft Drummer (Music)
Soft Drummer 1.0 Device: iOS Universal Category: Music Price: $14.99, Version: 1.0 (iTunes) Description: Soft Drummer is the closest thing to a pro session subtle drummer in your pocket. Easy to use and fast, it's much more than a... | Read more »
Is GO Gear the Pokemon GO map app you...
Now that we've settled into something of a Pokemon GO status quo, the number one desire of most players can best be summed out by modifying a quote from Rod Tidwell of Jerry Maguire: "Show me the Pokemon!" [Read more] | Read more »
Rodeo Stampede update: Mountains, new an...
The Savannah and Jungle were just the beginning in Rodeo Stampede. Get ready to head for the Mountains. I think I heard that in a beer ad once. [Read more] | Read more »
COSMOS RINGS (Games)
COSMOS RINGS 1.0.0 Device: iOS iPhone Category: Games Price: $5.99, Version: 1.0.0 (iTunes) Description: This game cannot be played without the Apple Watch.Released anniversary sale until August 31,2016 PST! A tragic tale of time's... | Read more »
How to get started selling on Mercari
As far as ecommerce has come over the last decade or so, there's still a tremendous opportunity to make it easier for people to buy and sell goods. That's especially true when it comes to shopping apps, which should only continue to increase in... | Read more »
Human Anatomy Atlas 2017 Edition - Compl...
Human Anatomy Atlas 2017 Edition - Complete 3D Human Body 1.0.24 Device: iOS iPhone Category: Medical Price: $24.99, Version: 1.0.24 (iTunes) Description: | Read more »
Heroes of Normandie (Games)
Heroes of Normandie 1.5 Device: iOS Universal Category: Games Price: $14.99, Version: 1.5 (iTunes) Description: The game does not support iPhone 4s and below | Read more »
Why you should never power up Pokemon in...
There's no question that candy is dandy in Pokemon GO. You need big quantities of it to evolve your Pokemon, and when combined with stardust, it can be used to power up your favorite pocket monsters as well, making them more formidable for the gym... | Read more »
Webzen launches 3D MMORPG MU Origin on i...
Mu Origin is featured time and time again at the very top of App Stores in China, and within the top five worldwide top-grossing charts on Google Play.Its popularity in Korea and China, featuring more than 120 registered players in China and 6... | Read more »
Severed (Games)
Severed 1.0 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0 (iTunes) Description: LAUNCH DISCOUNT ON NOW!! ENDS AUGUST 4! ==== Take control of a one-armed warrior named Sasha, wielding a living sword on her journey... | Read more »

Price Scanner via MacPrices.net

Second-Quarter Tablet Shipments Fell 4.8% –...
The latest report from the global market research firm TrendForce finds that worldwide tablet shipments for this second quarter totaled 33.54 million units, representing a quarterly drop of 4.8% and... Read more
Global Smartphone Sales Volumes Mark Second S...
According to preliminary results from the International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker, vendors shipped a total of 343.3 million smartphones worldwide in the second... Read more
Apple TVs on sale for $20-$40 off MSRP
Best Buy has 32GB and 64GB Apple TVs on sale for $20-$40 off MSRP on their online store. Choose free shipping or free local store pickup (if available). Sale prices for online orders only, in-store... Read more
Mac minis on sale for $50-$100 off MSRP
B&H Photo has Mac minis on sale for $50 off MSRP including free shipping plus NY sales tax only: - 1.4GHz Mac mini: $449 $50 off MSRP - 2.6GHz Mac mini: $649 $50 off MSRP - 2.8GHz Mac mini: $949... Read more
Clearance 2015 13-inch MacBook Airs available...
B&H Photo has clearance 2015 13″ MacBook Airs available for $300 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 1.6GHz/4GB/128GB MacBook Air (MJVE2LL/A): $799... Read more
Apple certified refurbished iPad mini 4s avai...
Apple has certified refurbished iPad mini 4s now available for up to $120 off the cost of new models. An Apple one-year warranty is included with each iPad, and shipping is free. The following models... Read more
Notebook Makers In No Rush To Adopt USB-C – R...
Digitimes’ Cage Chao and Joseph Tsai note that while the USB Type-C interface is enjoying growing popularity among smartphones and tablet makers, notebook and all-in-one (AIO) PC vendors (other than... Read more
iMacs on sale for up to $250 off MSRP
B&H Photo has 21″ and 27″ Apple iMacs on sale for up to $250 off MSRP including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2049 $250 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $... Read more
12-inch 1.1GHz Retina MacBooks on sale for up...
Amazon has 2016 12″ 1.1GHz/256GB Retina MacBooks on sale for up to $100 off MSRP including free shipping: - 12″ 1.1GHz Space Gray Retina MacBook: $1199 $100 off MSRP - 12″ 1.1GHz Silver Retina... Read more
Bare Bones Software Releases Free TextWrangle...
Bare Bones Software has announced the release and immediate availability of TextWrangler 5.5, a significant update to its powerful, free, general purpose text editor for Mac OS X. TextWrangler is a... Read more

Jobs Board

*Apple* Solutions Consultant - APPLE (United...
Job Summary As an Apple Solutions Consultant, you'll be the link between our future customers and our products. You'll showcase your entrepreneurial spirit as you Read more
Lead *Apple* Solutions Consultant - APPLE (...
Job Summary The Lead ASC is an Apple employee who serves as the Apple business manager and influencer across a number of Reseller locations. The Lead ASC's role Read more
*Apple* Retail - Multiple Positions, Charles...
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, Willow...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Evangelist - JAMF Software (United S...
The Apple Evangelist is responsible for building and cultivating strategic relationships with Apple 's small and mid-market business development field teams. This Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.