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 <> 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 - 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.


Community Search:
MacTech Search:

Software Updates via MacUpdate

Opera 40.0.2308.90 - High-performance We...
Opera is a fast and secure browser trusted by millions of users. With the intuitive interface, Speed Dial and visual bookmarks for organizing favorite sites, news feature with fresh, relevant content... Read more
BetterTouchTool 1.93 - Customize Multi-T...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
Backblaze - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Postbox 5.0.5 - Powerful and flexible em...
Postbox is a new email application that helps you organize your work life and get stuff done. It has all the elegance and simplicity of Apple Mail, but with more power and flexibility to manage even... Read more
Coda 2.5.19 - One-window Web development...
Coda is a powerful Web editor that puts everything in one place. An editor. Terminal. CSS. Files. With Coda 2, we went beyond expectations. With loads of new, much-requested features, a few surprises... Read more
Toast Titanium 15.1 - $99.99
Roxio Toast 15 Titanium, the leading DVD burner for Mac, makes burning even better, adding Roxio Secure Burn to protect your files on disc and USB in Mac- or Windows-compatible formats. Get more... Read more
Firetask 3.8.1 - Innovative task managem...
Firetask uniquely combines the advantages of classical priority-and-due-date-based task management with GTD. Stay focused and on top of your commitments - Firetask's "Today" view shows all relevant... Read more
Chromium 54.0.2840.71 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 54.0.2840.71: Release notes were unavailable... Read more
Chromium 54.0.2840.71 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 54.0.2840.71: Release notes were unavailable... Read more
Firetask 3.8.1 - Innovative task managem...
Firetask uniquely combines the advantages of classical priority-and-due-date-based task management with GTD. Stay focused and on top of your commitments - Firetask's "Today" view shows all relevant... Read more

Latest Forum Discussions

See All

WitchSpring2 (Games)
WitchSpring2 1.27 Device: iOS Universal Category: Games Price: $3.99, Version: 1.27 (iTunes) Description: This is the story of Luna, the Moonlight Witch as she sets out into the world. This is a sequel to Witch Spring. Witch Spring 2... | Read more »
Best Fiends Forever Guide: How to collec...
The fiendship in Seriously's hit Best Fiends has been upgraded this time around in Best Fiends Forever. It’s a fast-paced clicker with lots of color and style--kind of reminiscent of a ‘90s animal mascot game like Crash Bandicoot. The game... | Read more »
5 apps for the budding mixologist
Creating your own cocktails is something of an art form, requiring a knack for unique tastes and devising interesting combinations. It's easy to get started right in your own kitchen, though, even if you're a complete beginner. Try using one of... | Read more »
5 mobile strategy games to try when you...
Strategy enthusiasts everywhere are celebrating the release of Civilization VI this week, and so far everyone seems pretty satisfied with the first full release in the series since 2010. The series has always been about ultra-addictive gameplay... | Read more »
Popclaire talk to us about why The Virus...
Humanity has succumbed to a virus that’s spread throughout the world. Now the dead have risen with a hunger for human flesh, and all that remain are a few survivors. One of those survivors has just called you for help. That’s the plot in POPCLAIRE’... | Read more »
Oceans & Empires preview build sets...
Hugely ambitious sea battler Oceans & Empires is available to play in preview form now on Google Play - but download it quickly, as it’s setting sail away in just a few days. [Read more] | Read more »
Rusty Lake: Roots (Games)
Rusty Lake: Roots 1.1.4 Device: iOS Universal Category: Games Price: $2.99, Version: 1.1.4 (iTunes) Description: James Vanderboom's life drastically changes when he plants a special seed in the garden of the house he has inherited.... | Read more »
Flippy Bottle Extreme! and 3 other physi...
Flippy Bottle Extreme! takes on the bottle flipping craze with a bunch of increasingly tricky physics platforming puzzles. It's difficult and highly frustrating, but also addictive. When you begin to master the game, the sense of achievement is... | Read more »
Plants vs. Zombies Heroes guide: How to...
Plants vs. Zombies Heroes surprised us all, presenting a deep deck building experience. It's a great CCG that stands up well to the competition. There are a lot of CCGs vying for players' attention at the moment, but PvZ Heroes is definitely one... | Read more »
Arcane Online takes Online RPG’s to anot...
If you think that you need a desktop to enjoy high quality MMO gaming then Arcane Online hopes to prove you emphatically wrong. An epic fantasy Online RPG set in the land of Eldine, Arcane Online offers an abundance of features and content that... | Read more »

Price Scanner via

Apple’s Thursday “Hello Again” Event A Largel...
KGI Securities analyst Ming-Chi Kuo, who has a strong record of Apple hardware prediction accuracy, forecasts in a new note to investors released late last week that a long-overdue redo of the... Read more
12-inch Retina MacBooks on sale for $100 off...
Amazon has 2016 12″ Apple Retina MacBooks on sale for $100 off MSRP. Shipping is free: - 12″ 1.1GHz Silver Retina MacBook: $1199.99 $100 off MSRP - 12″ 1.1GHz Gold Retina MacBook: $1199.99 $100 off... Read more
Save up to $600 with Apple refurbished Mac Pr...
Apple has Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The following... Read more
PixelStyle Inexpensive Photo Editor For Mac W...
PixelStyle is an all-in-one Mac Photo Editor with a huge range of high-end filters including lighting, blurs, distortions, tilt-shift, shadows, glows and so forth. PixelStyle Photo Editor for Mac... Read more
13-inch MacBook Airs on sale for $100-$140 of...
B&H has 13″ MacBook Airs on sale for $100-$140 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only: - 13″ 1.6GHz/128GB MacBook Air (sku MMGF2LL/A): $899 $100 off... Read more
2.8GHz Mac mini available for $988, includes...
Adorama has the 2.8GHz Mac mini available for $988, $11 off MSRP, including a free copy of Apple’s 3-Year AppleCare Protection Plan. Shipping is free, and Adorama charges sales tax in NY & NJ... Read more
21-inch 3.1GHz 4K on sale for $1379, $120 off...
Adorama has the 21″ 3.1GHz 4K iMac on sale $1379.99. Shipping is free, and Adorama charges NY & NJ sales tax only. Their price is $120 off MSRP. To purchase an iMac at this price, you must first... Read more
Check Apple prices on any device with the iTr...
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
Apple, Samsung, Lead J.D. Power Smartphone Sa...
Customer satisfaction is much higher among smartphone owners currently subscribing to full-service wireless carriers, compared with those purchasing service through a non-contract carrier, according... Read more
Select 9-inch Apple WiFi iPad Pros on sale fo...
B&H Photo has select 9.7″ Apple WiFi iPad Pros on sale for up to $50 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 9″ Space Gray 256GB WiFi iPad Pro: $799 $0 off... Read more

Jobs Board

*Apple* Retail - Multiple Positions- Nashua,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions- Napervi...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Security Data Analyst - *Apple* Information...
…data sources need to be collected to allow Information Security to better protect Apple employees and customers from a wide range of threats.Act as the subject Read more
*Apple* Retail - Multiple Positions (Multi-L...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions- New Yor...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.