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Write Portable Code
Simon P. Chappell writes "Much as a certain large software company located in the North-West of the United States of America might wish otherwise, there are many different operating systems and platforms in use in the world today. Software these days needs to able to operate in a disparate environment, either by communicating with these other platforms or by running on them or, increasingly, doing both. The Information Systems industry is making good progress with the communication half of the problem (even if a lot of it seems to involve large amounts of XML), but it is still struggling with the issues inherent with writing portable code. Brian Hook's contribution to all of this is Write Portable Code , which according to it's subtitle is an introduction to developing software for multiple platforms." Read on for the rest of Simon's review.
Write Portable Code
author
Brian Hook
pages
248 (14 page index)
publisher
No Starch Press
rating
8/10
reviewer
Simon P. Chappell
ISBN
1593270569
summary
I recommend this book to anyone working with portable code.
This is a book for computer programmers who write software designed to run on multiple platforms. It's also for programmers who suspect that their software may need to run on different platforms. This brings the book onto the radar for free and open source software authors, as they seek to create software that does not trap their end users into using specific operating systems. The Structure
There is a good progression shown in the eighteen chapters of the book. The first couple of chapters introduce the reader to portability concepts and then to some of the specific portability features of ANSI C and C++ that are used throughout the rest of the book.
The middle chapters of the book, cover individual portability topics. Some of these topics are the obvious ones, like Floating Point numbers, Networking, Operating System, File System and Dynamic Libraries. Other topics are less intuitively associated with portability, but when you read the chapter, it's inclusion is both obvious and necessary. These subjects include Source Code Management, Compilers, Scalability and Data. There is more to portability than many of us might suspect.
The last two chapters look at some alternative ways of getting portability. Scripting languages are discussed and the pros and cons of each ones portability is weighed. Lastly the use of cross-platform libraries and toolkits is addressed. Quite apropos given that the book's author is also the author of a cross platform library.
As an example of the thoughtful approach taken in this book, lets' take a look at the chapter on scripting languages. It's about the shortest chapter in the book, but representative of the approach that Mr. Hook brings to his work. This chapter takes a very honest look at the portability and cross-platform aspects of using scripting languages. There are advantages and disadvantages to the use of scripting languages. The advantages include everything that is a disadvantage of low-level languages like C/C++. Scripting languages do not require you to worry about about memory allocation, bindings, System API calls or any of the other bugbears of a low-level language programmer's life. The disadvantages of scripting languages naturally include performance, given their interpreted natures, a general lack of tools, such as development environments or IDEs and their tendency to sit high above the operating system with a corresponding detachment from low-level facilities and services of that same operating system. Mr. Hook's choice of scripting languages to consider was interesting. I expected Ruby and Python; both popular and capable in their own right. The inclusion of JavaScript/ECMAScript was also not too unexpected, now that standalone versions are bubbling up and becoming available. The real surprise, albeit a pleasant one, was the inclusion of Lua; a scripting language designed for platform portability and which seems to have managed to fully mature without making a blip on most geeks radar screens.
I like that Mr. Hook has experience writing portable software. This matched with his authorship of the Portable Open Source Harness (POSH) portability library and his contributions to the Simple Audio Library (SAL) gives a great deal of credence to his writing.
This is a solid "doing" book. Mr. Hook is under no illusion that he's writing an introduction to programming. This book has a consistent purpose to take experienced programmers and fully equip them to deal with portability and it does not deviate from this in the slightest.
The layout of the book is first rate, with clear typography, comfortable spacing, clear diagrams and tables and nicely highlighted callouts. I did not notice any obvious typos or glitches in the book. While the look of a book is not the author's fault if it is below par, a well presented book can enhance the reading and learning experience.
The examples are as realistic as possible. While some of the examples to teach principles might be simpler, they are typically backed up with examples from either the POSH or SAL projects, showing real world portability coding. The level of C/C++ required to understand the examples is higher than many books that I've read. That's not to say that the code seems obfuscated, but it's code that is taking into account aspects of the real world and is, by necessity, not simple. A further positive quality of the code examples is that they're very well explained; well enough that an inexperienced programmer with determination could follow them and come to an understanding.
Appendix B contains a summary of all of the portability rules presented through the book. There are twenty rules and each is reprised with a small explanation/reminder of it's application. An example: Rule 4 - "Never read or write structures monolithically from or to memory. Always read and write structures one element at a time, so that endian, alignment, and size differences are factored out."
If you're looking for more of a fluffy "about" book, then this is not it. This is not a complaint, rather I offer it as something to consider, before you buy what you might otherwise think is a beginner's book.
I must reiterate the non-trivial C/C++ example code the book contains. This book is for serious programmers and is not afraid to role up it's sleeves and cut real code.
This is a very well written and very readable book. There are many aspects to the subject matter of portability and Mr. Hook addresses more of them than many of us had previously suspected existed and addresses them with firm authority. I recommend this book to anyone working with portable code."
You can purchase Write Portable Code from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
This is a book for computer programmers who write software designed to run on multiple platforms. It's also for programmers who suspect that their software may need to run on different platforms. This brings the book onto the radar for free and open source software authors, as they seek to create software that does not trap their end users into using specific operating systems. The Structure
There is a good progression shown in the eighteen chapters of the book. The first couple of chapters introduce the reader to portability concepts and then to some of the specific portability features of ANSI C and C++ that are used throughout the rest of the book.
The middle chapters of the book, cover individual portability topics. Some of these topics are the obvious ones, like Floating Point numbers, Networking, Operating System, File System and Dynamic Libraries. Other topics are less intuitively associated with portability, but when you read the chapter, it's inclusion is both obvious and necessary. These subjects include Source Code Management, Compilers, Scalability and Data. There is more to portability than many of us might suspect.
The last two chapters look at some alternative ways of getting portability. Scripting languages are discussed and the pros and cons of each ones portability is weighed. Lastly the use of cross-platform libraries and toolkits is addressed. Quite apropos given that the book's author is also the author of a cross platform library.
As an example of the thoughtful approach taken in this book, lets' take a look at the chapter on scripting languages. It's about the shortest chapter in the book, but representative of the approach that Mr. Hook brings to his work. This chapter takes a very honest look at the portability and cross-platform aspects of using scripting languages. There are advantages and disadvantages to the use of scripting languages. The advantages include everything that is a disadvantage of low-level languages like C/C++. Scripting languages do not require you to worry about about memory allocation, bindings, System API calls or any of the other bugbears of a low-level language programmer's life. The disadvantages of scripting languages naturally include performance, given their interpreted natures, a general lack of tools, such as development environments or IDEs and their tendency to sit high above the operating system with a corresponding detachment from low-level facilities and services of that same operating system. Mr. Hook's choice of scripting languages to consider was interesting. I expected Ruby and Python; both popular and capable in their own right. The inclusion of JavaScript/ECMAScript was also not too unexpected, now that standalone versions are bubbling up and becoming available. The real surprise, albeit a pleasant one, was the inclusion of Lua; a scripting language designed for platform portability and which seems to have managed to fully mature without making a blip on most geeks radar screens.
I like that Mr. Hook has experience writing portable software. This matched with his authorship of the Portable Open Source Harness (POSH) portability library and his contributions to the Simple Audio Library (SAL) gives a great deal of credence to his writing.
This is a solid "doing" book. Mr. Hook is under no illusion that he's writing an introduction to programming. This book has a consistent purpose to take experienced programmers and fully equip them to deal with portability and it does not deviate from this in the slightest.
The layout of the book is first rate, with clear typography, comfortable spacing, clear diagrams and tables and nicely highlighted callouts. I did not notice any obvious typos or glitches in the book. While the look of a book is not the author's fault if it is below par, a well presented book can enhance the reading and learning experience.
The examples are as realistic as possible. While some of the examples to teach principles might be simpler, they are typically backed up with examples from either the POSH or SAL projects, showing real world portability coding. The level of C/C++ required to understand the examples is higher than many books that I've read. That's not to say that the code seems obfuscated, but it's code that is taking into account aspects of the real world and is, by necessity, not simple. A further positive quality of the code examples is that they're very well explained; well enough that an inexperienced programmer with determination could follow them and come to an understanding.
Appendix B contains a summary of all of the portability rules presented through the book. There are twenty rules and each is reprised with a small explanation/reminder of it's application. An example: Rule 4 - "Never read or write structures monolithically from or to memory. Always read and write structures one element at a time, so that endian, alignment, and size differences are factored out."
If you're looking for more of a fluffy "about" book, then this is not it. This is not a complaint, rather I offer it as something to consider, before you buy what you might otherwise think is a beginner's book.
I must reiterate the non-trivial C/C++ example code the book contains. This book is for serious programmers and is not afraid to role up it's sleeves and cut real code.
This is a very well written and very readable book. There are many aspects to the subject matter of portability and Mr. Hook addresses more of them than many of us had previously suspected existed and addresses them with firm authority. I recommend this book to anyone working with portable code."
You can purchase Write Portable Code from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
Truly portable code is like flipping someone the bird.
No matter what country (OS) you're working in, everyone understands it!
Thank the ghods for the USB memory keyfob!
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Hey, just write whatever it is in Java. You know, "write once, run anywhere". Simple!!!
Yes, this is a joke.
and this is why web applications are becoming so popular...it's much easier to make something written in PHP and distributed through the web available to everyone than to try to port something in C++ across a bunch of platforms. imho this trend towards AJAX and more web applications is a good thing and makes it easier on developers trying to deal with clients on multiple platforms. i don't want to have to deal with porting applications (although cross-browser compatibilities offer their own complications).
What? Are you telling me that the OS I've been developing won't run on Windows, Linux, and OS X?
Whad` up wit` dat, fool?
How can I write portable versions of Mac OS X apps when the Cocoa API doesn't exist outside of Mac OS X (don't tell me about YellowBox or what-have-you) and the language Objective C isn't supported outside of Mac OS X (Apple is killing off Cocoa's Java support)? Oh, and the Carbon API doesn't exist outside of Mac OS X either (but at least it uses a widely supported language). You mentioned a software company in the Northwest US, but what about the one in Cupertino? Apps written to their platform are no more portable than Windows apps.
Besides that, apps that aren't able to take advantave of the underlying platform's unique features aren't sellable. Mac users in particular want apps that take advantage of the unique features of Mac OS X (and no, they don't consider some unix app to be a real "Mac" app, and rightly so). That means Cocoa or Carbon, and neither api is supported outside of Mac OS X.
-- "I never gave these stories much credence." - HAL 9000
I write simulations with GUI's in C++ exclusively and I develop in both Linux and XP (depends on the customer as to the final platform, but I code on both depening on where I am). Its easy to do c++ cross-platform. The only difference is I type "make" on the Linux box and "nmake" on the Windows box :P
hint: use standard C++ calls, don't get locked in to vendor-specific functions, use cross-platform libraries for the rest (opengl, xerces, etc.)
-everphilski-
"as a certain large software company located in the North-West of the United States of America might wish otherwise, there are many different operating systems and platforms in use in the world today. "
If his first sentence isn't trolling I don't know what is. Why is it ok to do it against MS, but nobody else?
You do it against MS, you make the front page, against apple you get flamed.
I got my first job and started digging into some code that was written for portability, it all seemed so obfuscated.
I was like, "Why are they #defining all their data types to something else? And what's with all the crazy compiler directives?" It seemed like they were going out of their way to make the code less readable.
Once I figured out that it was all there so that the code could be recompiled for different platforms, it all clicked together. It's really cool, and I'm pissed that I got out of college not knowing this stuff. It should be a required course, IMHO.
"If you haven't ported your code, it isn't portable."
Sticking to the libraries and (subsets of) languages that are really portable helps, too, like this book appears to cover, but if you just start off on a small mix of platforms, it becomes usually quite trivial to port to others. My Ostiary program runs on (at least) Linux, *BSD, OSX, Solaris, HP-UX, AIX, Tru64, IRIX, and Cygwin. I've written commercial code that runs on all of those plus Windows, NetWare, and OpenVMS, though that requires a few more #ifdefs.
PHEM - party like it's 1997-2003!
are done w/ J2SE using SWT as the front end. Looks like a native app, runs super fast since it relies on native widgets, and portability issues are largely mitigated for me.
Is this the same Brian Hook that previously worked at id software??
Java doesn't run everywhere: For instance, there is no Java JVM for a Palm. C/C++ programs that started elsewhere have been ported to Palm, on occasion.
It's a bit of an extreme case, I admit, but...
'Sensible' is a curse word.
Then device drivers and operating systems were going to let us abstract away the details of the underlying implementation of the hardware, letting us write portable code. But not all O/S versions are compatible; there are glibc issues under Linux, and so on.
Then JAVA was going to be completely portable to all operating systems. But not all Java virtual machines are identical, and different version of Java came out, and things diverged.
All of these things made life more portable, to some degree. All of them still require boostrapping a system that understands the underlying hardware and deals with it efficiently; then abstracts all that hardware specific efficiency away again.
Portability is *hard*: in some sense, it's the enemy of efficiency. You need to abstract away all those nice hardware specifics that make the hardware work, and replace them with a theoretical construct that caters to the lowest common denominator that you're willing to support.
What's worse, as soon as someone makes a different design decision, or an improvement, or something that isn't universally adopted all at once, you have multiple versions -- divergent standards which aren't completely compatible. It happened with UNIX; it's happening with Linux (to a lesser extent, because code can merge again after a fork), and it happened with C and Java.
What can the developer do? Just our best; true universal portability is a Holy Grail that we'll never attain, because the day we do, someone will invent a radical new system that doesn't quite fit our abstraction model...
Amen, brother.
.ini files, or CStrings, or what have you. It was all the non-portable things they did without even knowing it--and the fact that the non-portable stuff was salted and peppered evenly throughout the whole project instead of concentrated in a few well-defined modules--that got to me.
I've been involved in way too many projects where people said, "Oh, yeah, we're doing all our development on Windows but it's no big deal. We aren't going to use anything non-portable."
Then, when the time came to port it... it was utterly intertwingled with Windows-specific cruft, half of which crept in because nobody even knew they were doing it. If they'd ever tried even once to port it, they could have caught this stuff as it happened.
I don't mind a conscious decision to use
And it didn't help that everything was compiled with permissive compiler options regarding C/C++ conformance, and a low warning level.
"How to Do Nothing," kids activities, back in print!
I've written production code in C, C++, Objective-C, Lisp, Pascal, many different scripting languages, and Java. Bar none, if you want to write something portable, Java is the language to use. It has the incredibly complete and mature libraries, performance is excellent, tool support with IDE's and app servers and source repositories is fabulous, and it is designed to be cross platform! Games, huge transactional systems, office apps, and utilities are all appropriate types of applications to build on Java. I've started to do scripting on FreeBSD with Java. I'll admit, it's hard to write a useful bit of Java that is less than about 10 lines of code, particularly for text processing. But that is probably the only place it is lacking. The one other place one might consider using something else is in Dynamic Client-Side Web Apps (AJAX stuff). Other than that, I always groan when people talk about using other languages for cross-platform development.
Helping with organizational effectiveness is our job.
Isn't an OS just a kind of runtime environment? After all, it's just one level of abstraction among many levels of abstraction. A Java Virtual Machine is just one more level of abstraction.
This is my sig. There are many like it, but this one is mine.
If the task is well defined, a small, tightly defined app tied very closely to the target API has a better chance of performing well with fewer bugs as you can spend the portability-effort in testing.
I abstract math and models to generic C++. I tie the rest as tightly as possible to the target API and focus on being fast and bug free. In my career so far, the only code I have ever ported for business reasons ($$) has been mathmatical algorithm related.
YMMV.
..don't panic
I write portable code, I'm writing on Windows, deploying to an AMD Solaris box and the target is SPARC. I've also done this same "magic" trick on AS/400 and OS/360...
Now me I just use the tool designed for the job of being platform portable, rather than trying to invent new standard headers (STL anyone?) that address a fraction of the problem.
Want to do sound on multiple platforms? Graphics? Business Process? Then use Java, its what it was designed to do. And to all those muppets who shout "its not possible"... the deploy has just finished and within 30 seconds its running on two different platforms.
An Eye for an Eye will make the whole world blind - Gandhi
C++ also has some very nicely organized ways you can write portable code. For example, data serialization - if I care about a piece of code being portable, all of my "structures" that may need to be shared are classes with the functions "serialize" and "deserialize", and all of the member variables/structures are classes with such functions (down to the most simple members, which are just wrappers around basic types; you can even wrap vectors and maps so that arrays of any kind are dealt with automatically). Each class's serialize function simply calls the serialize function on all of its members that need to be preserved; only the most basic types actually do any IO themselves.
The net effect is that no matter how you change your code, or even if you template it over a range of types, everything always gets written out and read back in properly without having to resort to constantly changing special case read/write functions or having to know what is in every structure and how to write it. It keeps it very simple indeed. You could have a structure nested twenty levels deep containing arrays (vectors) and associative arrays (maps), and go in and change a dozen datatypes at different levels, and not have to modify a single piece of reading/writing code.
He's just being nice so my real father won't freeze him in carbonite and sell him for spice.
My team's been writing 100% portable C code since 1991 or so. We took the same approach that Apache has done since version 2, i.e. build a distinct portability library and remove all non-portable code from the application itself.
It's amazing anyone would actually write non-portable code except through ignorance. As a programmer, I still run code written in 1991-2 (though it's been marginalised by newer work), and we have made some quite complex products (web servers, code generators) that run on anything that has standard C libraries and BSD-style TCP/IP, including OS/2, OpenVMS, and of course all Unix and Windows boxes.
The alternative option is to use a VM. Since we write fast system software that's not an option.
A wise person taught me this over 20 years ago: life is too short to throw out code just because some platform changed. Portability is one of those skills that lets a normal programmer like me accumulate enough quality code over time to become a master programmer.
My blog
Apache Portable Runtime.
td
hard core geek-ware
That's right, you heard me. Don't write portable code.
Use portable libraries and languages; re-factor your working code to be portable; make high-level choices that support portability (e.g. don't lock yourself in to proprietary solutions), but don't write portable code.
Why? Because premature portability, like premature optimization is a red herring that steals your attention from the only two things that will ever matter: correctness and maintainability. Write correct code. Write verifiably correct code. Write maintainable code. Do these things and you are done. Then, port it to another platform or ten and optimize the hell out of it. Don't do these things up-front, as they buy you nothing on the first pass, and doing them later will give you the chance to re-consider the structure of your system which you should do at least twice before your first release anyway.
That said, do not snub portability unduely. If you have the choice of trivially supporting or not supporting portability-enhacing features (e.g. in your choice of a configure/build system), there's no reason not to be portable. Just don't let it set priorities for your project from day one.
2) Only if it is programmed that way... a developer can force a specific Look and Feel.
3) If by forever you mean 4) Again, only if it is programmed that way.
5) From a purist perspective, I'll grant you this one. But from a practical perspective, it's just not a big deal. Lots of JVM's out there, source code is available (although it's not Free).
Helping with organizational effectiveness is our job.
Hmmmm, IBM and PalmSource might disagree with you there.
But you're correct in general. Not every platform you'll want to port code to will have a JVM. And those that do will not have the right JVM
For instance, there is no Java JVM for a Palm.
There isn't? What will I do?
Dude. Java is everywhere. It's in tiny little cards and in the latest ARM processors. You can't run. You can't hide. Java will find your OS, and you will be assimilated. Submit to the collective!
Javascript + Nintendo DSi = DSiCade
Write on the bare silicon, with a microscope and an electron beam.
Compilers are for feebs who can't read schmatics!
Portability is for indecisive cowards!
sigs, as if you care.
Unfortunately, all too many Linux programmers are not writing to POSIX standards themselves. Far too many "Linuxisms" abound.
hello dear sirs my name is jamesh i are india (bihar) can u guide me install red had linux 9?
Write Once Compile Anywhere will never be completely realized since various systems have incompatible design goals. No matter how portable you've made your command line application, it probably won't make a lot of sense on a Palm. That's not a limitation of your code or PalmOS, but an acknowledgment that they're different animals.
Dewey, what part of this looks like authorities should be involved?
I had to take a mandatory graduate level course CS 533 Developing portable software, taught by Dr. Mooney, who was known around school as "that portability guy".
The class went thru umpteen strategies to write portable code & culminated in a portability project, where you wrote a "Quiz Program" in C, that ran on Solaris, Windows & the Mac with minimum code changes.
All code changes had to be confided to the stdio.h & other header libraries. I see these days he has added Java to the mix.
My own experience has been that it has very limited utility in real-life ie. corporate IT. All the jobs I held since I graduated did not require an ounce of thinking portable. They were all about writing proprietary code to be run off the web, and for some 10 years, Java was the only option until C# came along. So I practised portability by default, since that was the nature of my employment in the industry. But I can see how this might be useful for somebody doing systems level programming (assuming there are still such jobs in the IT industry in the US, of course...)
Note: I am a C++ programmer. I didn't read the book, just the review here. Apologies in advance if anyone takes offense.
> The first couple of chapters introduce the reader to portability concepts
> and then to some of the specific portability features of ANSI C and C++
> that are used throughout the rest of the book.
I think enough software is written in languages other than C and C++ that any serious author should put C or C++ in the title when the book is C or C++ specific.
It's not wrong that the author or publisher chose to call the book "Write Portable Code" instead of "Write Portable Code in ANSI C". But it does make me question if the author's knowledge is limited by a single-language bias.
> The last two chapters look at some alternative ways of getting portability.
> Scripting languages are discussed and the pros and cons of each ones
> portability is weighed. Lastly the use of cross-platform libraries and
> toolkits is addressed.
Given that scripting is limited to one chapter, wouldn't it have been better to refer the reader to other works with more detail and value, and only give a paragraph or so? Particularly since the book is not trying to be about portable code in general, but portability in ANSI C, and discusses nothing (AFAIK) about higher-level compiled languages.
The book's about C. Why clutter it with a chapter on Ruby, Python, and JavaScript/ECMAScript and say nothing about Java, Lisp, SmallTalk, etc? Writing a chapter on scripting languages strikes me as gratuitous filler.
And any non-trivial cross-platform C application is likely to use some sort of cross-platform toolkit. So why only a chapter?
> An example: Rule 4 - "Never read or write structures monolithically from or
> to memory. Always read and write structures one element at a time, so that
> endian, alignment, and size differences are factored out."
Writing structures one element at a time is a -minimum- required for portability. It doesn't completely address byte-order issues, variable internal data representations, or data element size issues. It just ensures that structure packing and alignment issues that might change based on compiler flags are covered. But change the compiler or platform and all these issues are still there even if you write the data elements singly. They are all unspecified or incompletely specified in ANSI C.
It's better to design a complete data representation format, including embedded version information, or just use a higher level data store engine.
My concern is that many of the other rules in the book might be similarly too "low-level" and incompletely specified. Rather than teaching inherently better, more portable coding techniques, they might just be teaching how to work around the low-level nature of C.
I know you're kidding, but unfortunately there are a lot of responses here which indicate that Java is the end-all and be-all of portable programming.
I'm sorry folks. Such people have never done real cross-platform programming. Java simply isn't an option on MANY platforms. If all you do is x86 platforms, and perhaps some Motorola workstation-class platforms, hey, you're fine.
But that's not the real world.
The real world includes MIPS, ARM and other processors. What's more, the embedded world makes up most of the usage of CPU's. Java is not an option in most cases, unless you go out and pay one of the few small shops that will port it a bunch of money. And that assumes your system have the footprint and horsepower to run it.
I see outfits where the programmers have never programmed on a non-x86 system in their life suddenly wake up to this fact. It would be funny if it wasn't so sad.
Now, granted the GNU folks are coming up with their Open Source version, and it appears to be coming along fine. But it's not quite there yet.
Also, keep in mind that it won't run on many platforms, simply because of size limitations. All the world isn't your dual-core 3 GHz x86 with 4 GB of RAM.
And I'm sorry, but the Java claims that it is as fast as C code just aren't true. Don't believe me? Try doing some benchmarks on 100 MHz small-RAM systems. If you're lucky enough to get it to fit, you'll see that things are just dog slow.
Most programmers and students today are just too used to working with the supercomputer type of CPU's that the modern desktop is like, and aren't used to dealing with small-footprint type of systems which make up most of the world
gotta... ...ugh... ...carry... ...all... *pant* ...that... *wheeze* ... run time type information ...around. Whew!
:-)
;-)
And yet, Java programs tend to compile to smaller files than native code, and also take a far shorter period of time. Even on the largest projects, I can compile Java code inside of ten minutes. It can take days to compile a C program of comperable size. And once it's in bytecode, it's only a short hop for the JVM to compile it to native code. Works pretty darn well.
Still, the whole idea of using RTTI to defer what should be a compile-time decision to run-time just leaves a bad taste in my mouth.
Not sure what you mean by this. Pretty much all code with direct references are properly checked at compile time. Obviously the run-time has to be a bit smarter when you dynamically load things via reflection, but that's very much a feature, not a bug.
Besides, you gotta love the ability to build a self-organizing program scheme in 20-30 lines of Java code. Doing the same thing in C++ is a PITA, and would only serve to confuse the heck out of the developer debugging the app and the OS trying to run it. I can just see it now, "Program X has 3,102 DLLs loaded."
Javascript + Nintendo DSi = DSiCade
Sun makes the Java install process on FreeBSD so complex that I've given up. Therefore any Java program instantly cannot run on my computers. So far I haven't seen any loss either. Java is mostly used for long running server processes (where JVM start up time is irrelevant and the JIT compiler can speed things to just as fast as C++), so I don't need it anyway.
I find that cross platform C++ is not hard if your code is properly modular. Libraries like QT or wxWidgets take care of most issues these days anyway.
I love how Anonymous Cowards like to slander and ridicule Slashdot, fully forgetting the fact that Slashdot is a free community service provided at a cost to those providing it, with little to no recompense. I also love how they attack the entire community for something one person writes in an article. It makes me feel all warm and fuzzy inside watching them make fools of themselves in their ignorance. Keep posting cowards, because THAT's how I make myself "feel bigger".
"For once, realize that not all of the worlds problems are caused by Microsoft."
You know, you are right, the rest of them are caused by people who complain about free services.
No conformist ever made history.
The second module deals with all the user interface stuff and nothing else. Any event handling is done in this module and nowhere else. That way, the rest of your code doesn't need to worry about what type of execution model is being used. It'll just work as you would expect. If there is no user interface, you don't need this module.
To make the UI truly portable is hard. No specific capability is guaranteed. eg: GUIs don't guarantee a text console, and text consoles don't guarantee a GUI. My advice would be to split the module into two sub-modules. The first sub-module handles what you want to do, but contains nothing specific on how. For example, it might be filled with commands for selecting fonts, drawing lines, etc. However, it would not contain any calls to an underlying system. It should assume some abstract, theoretical, idealized user interface.
The second sub-module (which may be a third-party library and not something you need to program at all) would then convert these commands into actual interface calls. If you're writing this yourself, I'd suggest starting with interfaces that are already fairly portable (eg: Qt, Gtk+, Ascii Art Library) where possible. If you can't, then you'll need to write alternative versions for different types of interface. But at least it's all in one place and squished down to the routine level, not entire screens.
The third sub-module (again, third-party if available) would do the same as above but for file I/O. Again, the upper levels should make no assumptions at all. "Anything is possible in the next half hour", as Gerry Anderson would say. The lower levels then convert the "ideal" into what the system can actually do. Here, there are at least some standards. Use them. But then write special case code for platforms that can do better. Portable need not mean sub-optimal, it merely means sub-optimal (but guaranteed to work) until tuned.
The fourth would do the same for networking. There is absolutely no reason why an application should know if you're using sockets, MPI message passing, IPv4, IPv6, DECNet or a guy waving two flags. At the application level, data comes in and goes out. The other end should be of no consequence, and the method of getting there should matter even less. High level networking should be abstract connections, using some sort of token to identify which connection is being referred to. There needs to be a middle layer here, to turn the abstract connection into a real networking protocol. The lowest level then handles the network calls required.
You need the three layers, because you've two levels of abstraction (the network protocol and the network hardware) and therefore you need two levels of reification to turn the abstract into something usable. As network protocols can work over multiple mechanisms, the protocols are resolved first and the mechanisms second.
Coding styles for ALL abstract components AND the first module should emphasize portability. There should be nothing system-specific there, so you should be able to use the absolutely vanilla ANSI specification of a language (where one exists). For C, if you want to cover ancient or obscure systems as well, you should duplicate all function declarations and external declarations, using a #ifdef to distinguish between ANSI C and K&R. There are probably other languages you need to support multiple variants of, just keep the areas where you need to have compile-time or interpret-time selection kept to a minimum.
The low-level routines are only going to work on a limited range of systems, no matter what. Therefore, anything valid for that subset is fair
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I think all the proponents of Java kind of missed the point here. Not everything has or even NEEDS the level of horsepower that Java requires- and just adding more muscle isn't always in the chips.
And even then, saying "Java" will run everywhere, is really a mis-concept. It'll run most everywhere where there is a least common denominator. I can tell you that while it makes it easier for Oddlabs to make Tribal Trouble for three platforms simultaneously, Java doesn't make it cross-platform- you can't take it and run it on say a Solaris box (though I suspect they could MAKE a Solaris iteration of the game easily enough...) or on an embedded machine using Java, say like the Ignite platform.
Java makes some things "easier" to make cross-platform, but again, it's like anything else- cross-platform is more of a philosophy than a feature set of a language or toolset. And it's definitely NOT the panacea that the proponents in this thread make it out to be- I should know, I do Java development amongst other things. If you can't make a C++ program at least 40% faster than your best Java code, you might want to re-work the C++ code. This is not to say that it's a bad idea or anything; it's just that people keep trying to jam it into problem sets that it's ill suited for.
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For enterprise strength app servers WebLogic and WebSphere are written in Java. Not as scalable but getting better is Tomcat also written in Java. The Java application I work on processes about 10 million transactions a week and was ported from the mainframe. The biggest porting headache was not the Java code but SQL differences between DB2 and Oracle. In terms of cost per transaction it's cheaper than many of our mainframe apps.
For development Eclipse is written in Java using SWT. Eclipse has become the new standard for open IDE tools.
Up until I lost it in a machine crash I had a Java email program program that I ran using Java 1.1 through to 1.5 on Linux, Windows and MacOS. When was the last time you had a program that didn't even need to be recompiled through 4 major operating system releases let alone as you moved it from OS to OS. Heck, with Linux a 0.0.1 change in the kernal could force a recompile.
Now, for pure number crunching Java is definitely not the right choice but most apps are not simply churning the CPU. Most real life apps also involve disk I/O, network I/O, etc. If 90% of your app is I/O then it's not going to make much of a difference what technology you use on the other 10%. So why not use Java and make it portable as well.
With Java, what you gain in portability, isolation from OS releases and a wealth of open source APIs far outweigh the less than 5% (yes it's that little) overhead that the Java runtime adds to 10% of your app.
Some of what I say is fact, some is conjecture, the rest I'm just blowing out my ass...you guess.
If you want a cross-platform GUI, then I think Java/Swing is the way to go a lot of the time.
I program mainly in Java and C++, and if you are looking just at desktop machines (which is what I work with) then it's really not a big deal either way since you are mainly looking at *nix, Windows and maybe OS X. Swing is pretty much write-once for all three platforms- though you have to do some funkyness to get mac programs to look like mac programs under OS X. Qt is available for all three platforms as well. Athough I've never developed with it, AFAIK GTK+ is also available on OS X, as well as *nix and Windows.
The thing is, it's no longer unreasonable to expect to write an application and have it run on a desktop system, a cell phone, and a PDA. Since most cellphones support at least a subset of Java, whereas I do not know of any that support Qt or GTK+, it seems that in these instances Java is the way to go.
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Lua is quite big among game developers, and I suspect that's why it's on Brian Hook's radar screen, Brian having spent a good amount of time in the game dev arena. Why is it popular with game developers? For one, because when they look for portability, they really need portability. Often all the way from dual proc Wintel boxes right down to GBA. This is possible in part because Lua is apparently quite light weight in terms of memory requirements unlike most other scripting languages.
On a side note, generic programming in C++ is very much a joke. I mean, you cannot even define constraints on template arguments, and have to resort to dirty tricks with delayed instantiation - WTF?
The problem with C++ libs is that very few of them adhere to the C++ philosophy, and thus play well with STL and boost. Most are, at best, "C with classes". Quite a few are essentially Java redone in C++ (Qt being the most prominent example). Generic programming, full-scale use of templates, STL-compatible iterators? A rare sight, unfortunately.Anyway, if you know a decent cross-platform GUI toolkit written in and for proper C++, please do tell (gtkmm comes close, but it's not really cross-platform enough, and some design decisions, such as ustring, are questionable). I've been looking for that for ages, and got desperate enough that I might well start writing one myself.