Do C++ programmers need to know Linux perfectly as well?

[2kaud]

I deleted the post on my own initiative because I realized it might be offensive to Linux/C programmers.

Each forum has a limit for what's passable and I didn't want to push it but if you feel it's acceptable please restore it.

[Post restored with minor edit]

[laserlight]

I'd say to take Linus Torvald's comments with a grain of salt: while it is clearly representative of what he expects of Linux kernel developers, and reflects his opinions of those who would program in C++ for Linux, it isn't representative of the varied opinions of C and C++ that you can find among programmers who program for Linux using C and/or C++. I have indeed encountered the type of programmers that wolle mentioned, but it seems to me to be a contrived stereotype. Mind the different cultures involved, but don't be prejudiced as every workplace, team, or project is different.

[superbonzo]

Going to C is backing one step, while a clever person moves frontwards. I'm a fan of C++ and will never leave it for c.
Thanks very much for your comments.

this is a wrong attitude in my opinion; C++ is not a ‘clever’ version of C, you don’t use one or the other based on how smart you are or on which fan you are of.

C and C++ have different stregths and, despite sharing a similar syntax and being designed to be tightly interoperable, are totally different languages that diverged considerably in the last few decades.

C++ is capable of much more powerful abstractions, but this happens at the cost of a considerably more complex object model. As a result, it’s comparatively much harder to guess what a compiler will generate by looking to a piece of C++ code, if possible at all, and it’s comparatively much harder to ensure correctness and portability of lower level operations ( unless restricting to, ehm, the type system inherited from C ). Yes, C++ gives you all the tools to write lower level code if necessary but if (in your job) you find yourself in the need of tightly controlling space and time too often, C++ becomes antieconomical compared to C, this is what Linus is talking about and it makes a lot of sense honestly(*).

as an example, I'd bet very few programmer could implement std::vector<T> out of their head, without violating aliasing rules, object lifetime rules, alignment, etc... ( etc... ). Now, it's ok if you need to do this once or just few times in the lifetime of your product ( or none, if you use existing libraries ) but if this turns out the norm and you're not a library writer, then C is a much better suited tool.

(*) please, note that I do love C++ and I seldom ( if not ever ) code in C ...

[wolle]

I have indeed encountered the type of programmers that wolle mentioned, but it seems to me to be a contrived stereotype.

I hope you're right because Linus Torvalds isn't just anybody and when the top dog barks the puppies are likely to yelp along.

Even though Mr. Torvalds' main concern is the Linux kernel his standing is such that his tone of voice and personal views considerably influence the whole of the Linux community. He should've known better than to publish that C++ rant.

[wolle]

C and C++ have different stregths and, despite sharing a similar syntax and being designed to be tightly interoperable, are totally different languages that diverged considerably in the last few decades.

C isn't just tightly interoperable with C++, C is an integral part of C++. Each new C++ standard specifies which C standard it's based on. So since C is in the DNA of C++ it's not like you are avoiding C by using C++.

Still there are small (and annoying) differences between the C of C++ and the C language. That's undeniable but the major divergence isn't due to that but to the massive evolution of the part of C++ that isn't C.

I'm sure there are situations where the C language is the best choice but ever so often the C of C++ would be equally fine. It may even be so that C often is used simply because it's in the comfort zone of everybody concerned whereas C++ is a scary alien (that you better hate).

Unlike what many seem to think, C++ is not an all-or-nothing proposition. It's a perfectly fine strategy to use C of C++ as a baseline and then cherry-pick functionality from C++ that suits the situation.

This is the strategy Lockheed Martin took for their Joint Strike Fighter (F-35) project. They even enlisted Bjarne Stroustrup, the inventor of C++, to help work out suitable C++ guidelines called JSF++. Here's a presentation by Mr. Stroustrup where JSF++ is used as an example starting on page 25,

http://www.automotive2010.de/program...-Cplusplus.pdf

and here's a version of the complete guideline,

http://www.stroustrup.com/JSF-AV-rules.pdf

C++ becomes antieconomical compared to C, this is what Linus is talking about and it makes a lot of sense honestly(*).

The Linux kernel project started as a relatively small program with like ten thousand lines of code. Over the years it has grown to a huge beast and the number of lines now amount to millions.

Mr. Torvalds has openly admitted that there are quality problems. The kernel is bloated and huge and too complex. It has become inefficient and infested with bugs no one dares to correct for the fear of making things worse.

https://en.wikipedia.org/wiki/Criticism_of_Linux

Well, it's easy to write a small C program that is lean and mean. The problems come with growth as is typical for the procedural programming paradigm. It's possible to avoid this by enforcing object oriented and functional techniques on C code right from the start but apparently this has not been done with Linux. So here we are with a situation that is far from "economical" in spite of the alleged efficiency of C.

I'm not claiming using C++ would've been any better but it certainly would've been possible as the JSF project above indicates (where C++ even displaced Ada actually). And there are more examples of big complex programs of a systems nature being written in C++ like say several of the Java Virtual Machines.

[LMHmedchem]

As a practical note, I program in c and c++ using the gnu compilers in cygwin. Cygiwn provides a linux like environment that runs under windows. This allowed me to learn my way around linux (essentially the bash command line and associated tools) and also to program code that will compile, link, and run on either linux or windows.

As has been mentioned, there are differences in how the languages interact with the operating system that are important to understand. Methods for creating a new process, inter-process communication with pipes and shared memory, and others, are different in linux and windows, so any program that needs that functionality needs to be abstracted so that the right parts of your code base get compiled and linked depending on the OS your are building for. Overall, that is not that bad of an issue to manage.

I also like the eclipse IDE for c++ as it will run on either windows or linux. In my business, we need to program for all the different OSs in use, so it's nice to have your projects in an IDE that you can use on any platform.

LMHmedchem

[superbonzo]

Unlike what many seem to think, C++ is not an all-or-nothing proposition.

nenver said that, actually I claimed the exact opposite.

[...]in spite of the alleged efficiency of C.

you missed the point; this has nothing to do with efficiency as such, it has to do with correctness, that is proving that some low level operations will actually respect you requirements ( at the very basic, having defined behavior on some (set of) envirnoments ). This requires detailed knowledge of the language object model and evaluation semantics.

[wolle]

nenver said that, actually I claimed the exact opposite.

you missed the point;

It may also be that you said that and that I got your point but we'll never know because I'm not going to reply. I never do when someone argues ad hominem.