TweetFollow Us on Twitter

Feb 99 Factory Floor

Volume Number: 15 (1999)
Issue Number: 2
Column Tag: From The Factory Floor

Universal Interfaces Today

by Nick Kledzik and Dave Mark, ©1999 by Metrowerks, Inc., all rights reserved.

This month, the Factory Floor visits with Nick Kledzik, Apple's Universal Interface-meister. With our upcoming move to Carbon and MacOS X, the time seems right for an update and Nick was kind enough to give us one.

Nick Kledzik <kledzik@apple.com> has been a software engineer at Apple for over 11 years working on various toolbox managers. In '93 he wrote an internal coding style document called "Building Code" which lead him to his current work of managing the Mac OS API's. Recently he has been working on MRJ (Apple's Java VM), developing JDirect 2.0 which enables java code direct access to the Mac OS toolbox. When not working he's probably pampering his new wife or their cats: Catbert and Hobbes.

Dave: How did the Universal Interfaces get started?

Nick: Back in '93 the PowerMac team was working on the software to enable Macintoshes to use the PowerPC processor instead of the 68k family. The team quickly realized that the existing 68k headers were riddled with 68k-isms and could not be compiled by xlc, the only PowerPC compiler at the time. The first approach was a one shot tool to munge the headers to be compatible with xlc. But, alas, the rest of Apple's software teams continued to use and modify the 68k based headers, and the PowerPC headers were so different that merging and synchronizing changes proved to be an immense time sink.

The solution that evolved was to have a central repository called MasterInterfaces in which all headers were stored. The headers were an augmented form of the 68k headers with their names changed to end in .i instead of .h to ease build rules. A tool called Interfacer was developed which could read the .i files and generate "universal" C headers. The name "universal" was coined because they could be read by both 68k compilers and the PowerPC compiler.

This model proved to be very powerful. The Interfacer was enhanced to generate MixedMode glue for all the System APIs. When we discovered that a #pragma needed to be added to all .h files, all it took was one change to the Interfacer tool and all generated .h files were updated.

In early '94 I headed up a group to fully implement this model. We merged all Apple's public and private headers into MasterInterfaces and updated the Interfacer tool to also emit assembly and Pascal interfaces. The result was the 2.0 Universal Interfaces. Then I started getting serious about being "universal". My goal for the 3.0 Interfaces was that they would "just work" with every compiler on the planet. To do so, every compiler dependent aspect of the headers had to be conditionalized and the core file ConditionalMacros.h had to be able to recognize and auto-configure itself.

Dave: What's the difference between Universal Interfaces and Universal Headers?

Nick: Apple uses the term "interfaces" in the generic sense of the interface between an application and the OS. That's the "I" in API. Metrowerks organized their CodeWarrior CD by naming files for Pascal as "Interfaces" and for C as "Headers". The result was that the term "Universal Headers" was born to describe Apple's Universal Interfaces for C.

Dave: What process do you go through to generate each new batch of Universal Interfaces?

Nick: The overriding question is when to release. For this, I look for either a milestone release from Apple (such as Mac OS 8.1 or 8.5) or a tempting release vehicle such as a CodeWarrior CD release. Once the ship date is locked down, I review the bugs that developers have reported and work with the various engineering teams at Apple to make sure that all changes have been checked into MasterInterfaces. The build part is easy. The Interfacer tool now runs in a batch mode, which means the Interfacer tool is only run once and it emits the C, Pascal, Asm, and Rez files in parallel. The entire build of 750+ files takes under 3 minutes!

Dave: With each new release of the Universal Interfaces, most everyone's code breaks. What is Apple doing to address this problem?

Nick: I review changes in MasterInterfaces and categorize them as to their effect on developers:

  1. Transparent.
  2. Source compatible because of grandfathering of old names or types.
  3. Source compatible if developer changes #includes.
  4. Binary but not source compatible.
  5. Source but not binary compatible.
  6. Neither source nor binary compatible.

Over 95% of the changes are type 1 and are never noticed by developers. For the rest, I work with the engineering teams to make them type 2 by using #defines or typedefs inside of OLDROUTINENAMES so that a developer can make the changes at his leisure. But a few, like moving SysBeep from OSUtils.h to Sound.h, could not be changed to type 1 or 2 because Sound.h already included OSUtils.h and you can't have circular includes.

But, the detection and flagging of these changes is still a manual process and some still slip by me. In the future, Interfacer will become smarter and automatically issue warnings or errors when a source incompatible change is made to a .i file.

Dave: What exactly is Carbon?

Nick: Carbon refers to the subset of Mac OS APIs (functions) in Universal Interfaces that will be supported on Mac OS 8.1 through Mac OS X. In addition, the only clients of Carbon APIs should be application-level code (apps, plugins, shared libraries, etc.) In Mac OS X, drivers will be built using different headers and APIs than applications.

Dave: How will Carbon affect the Universal Interfaces?

Nick: The plan is for a future release of Universal Interfaces to support Carbon development. That is, we will be adding #if statements to the Universal Interfaces so that a developer can assert that he is targeting Carbon (as opposed to System 7 or Mac OS 8.x) and get compile time errors if his code calls any Mac OS function that is not in Carbon. Note, even if he does not assert he is targeting Carbon, he will still get a link time error because you link against different stub libraries when building applications for Carbon.

Dave: Does this mean we are going to have even more Stub Libraries?

Nick: At this time, the plan for Mac OS X is to have one CarbonLib stub library. I'm considering making a similar MacOS8Lib stub library which contains fragments for InterfaceLib, DragLib, SoundLib, etc. This will make it much easier for developers to figure out which stub libraries to use. The problem is there are enough cases where developers want or need a finer level of control (e.g. BlockZero from InterfaceLib vs DriverServicesLib), that I will probably need to ship both the high level conglomerate stub libraries (e.g. MacOS8Lib) and the low level individual stub libraries (e.g. InterfaceLib).

Dave: What changes do you see coming down the pike for programmers who want to call the Mac Toolbox directly from their Java programs?

Nick: Java has and will continue to become faster and easier to use on Macs. But, there is a fundamental impedance mismatch between Java and the Mac OS toolbox. Java is an object oriented language with garbage collection and a theoretically uncrashable runtime. The Mac OS toolbox is none of those things.

Java programmers have a couple of options for easy access to the Mac OS toolbox:

  • Use the standard Java classes such as java.io.File - The implementation of those standard classes on MRJ will "do the right thing" on the Mac OS, such as setting file types and creators via Internet Config.
  • Use packages written specifically for java clients who want to access toolbox functionality such as QuickTime for Java or MRJToolkit.
  • MRJ 2.1 contains a feature called JDirect which allows Java code to easily call into Mac OS shared libraries and the MRJ 2.1 SDK contains java bindings generated by the Interfacer tool. The combination allows developers to call any Mac OS API directly from Java. But, the developer still has to write Java code to handle things like Pascal strings, memory allocation and deallocation, etc.

As time goes on, Apple and third parties will continue to write more Java packages which make it easier to use Mac OS specific functionality from Java. It is an open question whether anyone will write a Mac OS only framework in Java (a la MacApp).

Dave: In a similar vein, what changes do you see for C++ and Pascal programmers?

Nick: The Mac OS toolbox has standardized on procedural ABIs (application binary interfaces). This has enabled applications to be written in most any language. It is unlikely that any non-procedural features (e.g. C++ objects) will be added to the Mac OS APIs. These sorts of things should be layered onto the Universal Interfaces as is done with PowerPlant.

There are a few C++ things which do make sense in the Universal Interfaces such as inlined functions instead of parameterized macros and the use of name spaces. These are both on my to-do list.

Pascal Interfaces will continue to be generated from MasterInterfaces. But, because Pascal has not been standardized the way C has, developers using different Pascal compilers have needed to modify Apple's Universal Interfaces for Pascal to work with their compiler. Since Pascal does not have a preprocessor, there really is no way to make truly universal interfaces.

I think the long term solution for Pascal and other language support (e.g. Lisp, Fortran, Basic, etc.) is to open up the Interfacer tool. A current project of mine is researching how to deliver a "Universal Interfaces Kit" which contains the data and a framework for developers to generate their own interfaces.

 
AAPL
$519.01
Apple Inc.
+1.05
MSFT
$40.40
Microsoft Corpora
+0.65
GOOG
$556.54
Google Inc.
+20.10

MacTech Search:
Community Search:

Software Updates via MacUpdate

PDFpenPro 6.2 - Advanced PDF toolkit for...
PDFpenPro allows users to edit PDF's easily. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Create... Read more
PDFpen 6.2 - Edit and annotate PDFs with...
PDFpen allows users to easily edit PDF's. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Features... Read more
Monolingual 1.5.9 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. It requires a 64-bit capable Intel-based Mac and at least... Read more
Maya 2015 - Professional 3D modeling and...
Maya is an award-winning software and powerful, integrated 3D modeling, animation, visual effects, and rendering solution. Because Maya is based on an open architecture, all your work can be scripted... Read more
Starcraft II: Wings of Liberty 1.1.1.180...
Download the patch by launching the Starcraft II game and downloading it through the Battle.net connection within the app. Starcraft II: Wings of Liberty is a strategy game played in real-time. You... Read more
Sibelius 7.5.0 - Music notation solution...
Sibelius is the world's best-selling music notation software for Mac. It is as intuitive to use as a pen, yet so powerful that it does most things in less than the blink of an eye. The demo includes... Read more
Typinator 5.9 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
MYStuff Pro 2.0.16 - Create inventories...
MYStuff Pro is the most flexible way to create detail-rich inventories for your home or small business. Add items to MYStuff by dragging and dropping existing information, uploading new images, or... Read more
TurboTax 2013.r17.002 - Manage your 2013...
TurboTax guides you through your tax return step by step, does all the calculations, and checks your return for errors and overlooked deductions. It lets you file your return electronically to get... Read more
TrailRunner 3.8.769 - Route planning for...
Note: While the software is classified as freeware, it is actually donationware. Please consider making a donation to help support development. TrailRunner is the perfect companion for runners,... Read more

Latest Forum Discussions

See All

Hearthstone: Heroes of Warcraft is Avail...
Hearthstone: Heroes of Warcraft is Available on the U.S. App Store Right Now – Gogogogo! Posted by Rob Rich on April 16th, 2014 [ permalink ] | Read more »
Groundskeeper2 Review
Groundskeeper2 Review By Nadia Oxford on April 16th, 2014 Our Rating: :: SLICE THOSE ALIEN SLIMEUniversal App - Designed for iPhone and iPad Putting aside some minor control issues, Groundskeeper2 is a fun and furious action/... | Read more »
Pinnacle Studio for iPhone (Photography...
Pinnacle Studio for iPhone 5.0 Device: iOS iPhone Category: Photography Price: $9.99, Version: 5.0 (iTunes) Description: | Read more »
Season 3 of Zombies, Run! Starts Right N...
Season 3 of Zombies, Run! | Read more »
Snupps Review
Snupps Review By Jennifer Allen on April 16th, 2014 Our Rating: :: USEFUL LISTINGUniversal App - Designed for iPhone and iPad Got a huge collection that you need to organize, or just want to share with others? Snupps has it covered... | Read more »
Toad Rider Goes Free for a Limited Time,...
Toad Rider Goes Free for a Limited Time, Starting This Week Posted by Tre Lawrence on April 16th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Knights of Pen & Paper is Free for a...
Knights of Pen & Paper is Free for a Limited Time – Don’t Wait for a Natural 20, Get it Now! Posted by Rob Rich on April 16th, 2014 [ permalink ] | Read more »
R.B.I. Baseball 14 Review
R.B.I. Baseball 14 Review By Blake Grundman on April 16th, 2014 Our Rating: :: RETRO REVIVEDUniversal App - Designed for iPhone and iPad What was old is new again, as the MLB attempts to taking baseball gaming back to its retro... | Read more »
Noodlecake Studios Places Mikey Hooks on...
Noodlecake Studios Places Mikey Hooks on Sale, Releases Sneak Peek Trailer for Upcoming Sequel Mikey Boots Posted by Tre Lawrence on April 16th, 2014 [ | Read more »
Cosmic Mechanic Review
Cosmic Mechanic Review By Blake Grundman on April 16th, 2014 Our Rating: :: SLIGHTLY CREDIBLE MACHINEUniversal App - Designed for iPhone and iPad Creatives folks love the opportunity to have their wits tested, but there isn’t... | Read more »

Price Scanner via MacPrices.net

Microsoft Blinks – Drops Microsoft Office 365...
Microsoft has dropped the annual subscription fee for Microsoft Office 365 Personal – which is needed in order to create and edit documents in Microsoft Office for iPad. However, Apple’s iOS and OS X... Read more
New AVG Vault Apps for iOS and Android Help K...
AVG Technologies N.V. an online security company for 177 million active users, has announced the launch of its latest mobile application, AVG Vault. The free app introduces an innovative user... Read more
Free Local Carrot iPhone App Helps Find Fresh...
I love fresh vegetables. I’m not a vegan, although I was for several years in the 1980s, but fresh vegetables and other whole foods are still my dietary mainstays as a matter of taste rather than... Read more
Apple refurbished iPad Airs available startin...
Apple is now offering Certified Refurbished iPad Airs for up to $140 off MSRP. Apple’s one-year warranty is included with each model, and shipping is free. The following Airs are available today: -... Read more
21-inch 2.7GHz iMac on sale for $1179, save $...
B&H Photo has the 21″ 2.7GHz iMac on sale for $1179 including free shipping plus NY sales tax only. Their price is $120 off MSRP. Add an iMac to your shopping cart, and B&H will offer an... Read more
Download our app, iTracx, for iOS and Android
MacPrices is proud to offer readers a free iOS app (iPhones, iPads, & iPod touch) and Android app (Google Play and Amazon App Store) called iTracx, which allows you to glance at today’s lowest... Read more
Education discounts shave up to $300 off the...
Purchase a new Mac at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free, and all... Read more
Save $50 on Mac mini Server
B&H Photo has the 2012 Mac mini Server on sale for $949 including free shipping plus NY sales tax only. Their price is $50 off MSRP. Read more
PhatWare’s “Ultimate Writing App For iOS” Ren...
PhatWare Corp. has announced it has renamed its new WritePro word processing app for iPhone and iPad: WritePad Pro. The decision to change the app’s name to leverages the strong brand awareness and... Read more
Full Resolution Photo Editor Tint Mint 1.0 Re...
California based independent developer, Jeffrey Sun, creator of the iOS app Modern Editor, has released Tint Mint, a new photography app for editing enthusiasts. The app costs a dollar, and it packs... Read more

Jobs Board

*Apple* Retail - Manager - Apple (United Sta...
Job SummaryKeeping an Apple Store thriving requires a diverse set of leadership skills, and as a Manager, you're a master of them all. In the store's fast-paced, dynamic 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
*Apple* Retail - Market Leader - Cincinnati...
…challenges of developing individuals, building teams, and affecting growth across Apple Stores. You demonstrate successful leadership ability - focusing on excellence Read more
*Apple* Retail - Manager - SoHo - Apple (Uni...
Job SummaryKeeping an Apple Store thriving requires a diverse set of leadership skills, and as a Manager, you're a master of them all. In the store's fast-paced, dynamic Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** Every day, business customers come to the Apple Store to discover what powerful, easy-to-use Apple products can do for them. As a Business Leader, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.