My advice on implementing stuff in C: [LWN.net]

My advice on implementing stuff in C:

Posted Oct 15, 2010 18:22 UTC (Fri) by chad.netzer (subscriber, #4257)
In reply to: My advice on implementing stuff in C: by HelloWorld
Parent article: Russell: On C Library Implementation

> then perhaps you shouldn't be programming at all

That suggestion seems overly condescending.

> (at least not low level programming, which is what C++ is about).

I assert that "low level programming" is *not* what C++ is about. Modern C++ style recommends that you use smart pointers, rather than C pointers, for example. Nor should you be using C strings, C arrays, C structures, C stdlib functions, C-like error handling, C macros, etc. Basically, modern C++ encourages using full high-level abstractions for data structures and algorithms, and is thus, fundamentally, high-level. And when all these new features and abstractions are used properly, it can be a beautiful, elegant thing IMO (that takes a lot of time and memory to compile). But it's not low-level.

The fact that many people still want to use C++ as only "a better C" (ie. no exceptions, multiple inheritance, namespaces, virtual functions, the stdlib, RTTI, or even templates and RAII), and thus *not* use the new features added in the last 15 years, is a direct consequence of many of those features being "insanely complex".

But the C++ FAQ, and C++ FQA make both ends of this argument in a more elegant fashion than I can:

http://www.parashift.com/c++-faq-lite/index.html
http://yosefk.com/c++fqa/

Note how rarely the FAQ mentions pointers, btw.

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My advice on implementing stuff in C:

Posted Oct 15, 2010 19:40 UTC (Fri) by Ed_L. (guest, #24287) [Link] (1 responses)

"But its not low level."

To a certain extent its a circular argument. As others have observed, if you want to do system level (low level) programming on *nix, then you will ultimately end up calling libc, which libraries like glibmm admittedly do a wonderful job of wrapping. For the most part. But for that small part they don't, I've yet to find a substitute for just calling libc (or a syscall) directly. And for me that's one of the beautiful things about C++: its not dogmatic, and allows one to write grotty Fortran when nothing else will do.

:-)

My advice on implementing stuff in C:

Posted Oct 16, 2010 14:32 UTC (Sat) by Baylink (guest, #755) [Link]

> And for me that's one of the beautiful things about C++: its not dogmatic, and allows one to write grotty Fortran when nothing else will do.

How come that's not one of the Quotes of the Week?

My advice on implementing stuff in C:

Posted Oct 15, 2010 20:29 UTC (Fri) by HelloWorld (guest, #56129) [Link] (2 responses)

I assert that "low level programming" is *not* what C++ is about. Modern C++ style recommends that you use smart pointers, rather than C pointers, for example.

How does that make the language any less "low level"? A smart pointer just automates stuff you'd normally do by hand (i. e. free resources or decrement a reference counter). It's just as efficient

Nor should you be using C strings, C arrays, C structures, C stdlib functions, C-like error handling, C macros, etc. Basically, modern C++ encourages using full high-level abstractions for data structures and algorithms, and is thus, fundamentally, high-level.

The use of C arrays isn't discouraged because they're "low-level", but because there are better alternatives. std::tr1::array is just as low-level-ish as a C array, it does't do bounds checking or anything fancy, and it's just as efficient. The difference is that it offers the interface of an STL container, allowing you to use STL algorithms with it.

The same basically applies to C macros. The MAX(x,y) macro kind of works, but std::max(x,y) works better. It'll complain if x and y are not of the same type, and it won't evaluate its arguments more than once. std::max isn't somehow higher-level than MAX, it just sucks less.

Some things in C++ actually raise the level of abstraction, for example with std::string you don't have to worry about memory allocation any longer, since the class will do it for you when needed. If you can't afford that, nobody is going to blame you for not using it. C++ was deliberately designed not to force some style of programming on the user, be it a high or a low level one (unlike C, which forces you to program on a low level of abstraction all the time).

My advice on implementing stuff in C:

Posted Oct 15, 2010 22:49 UTC (Fri) by chad.netzer (subscriber, #4257) [Link] (1 responses)

> unlike C, which forces you to program on a low level of abstraction all the time

And so why did you claim above (while admonishing others) that: "low level programming [...] is what C++ is about"? My claim is that it is about much more than that. Agree?

My advice on implementing stuff in C:

Posted Oct 15, 2010 22:55 UTC (Fri) by HelloWorld (guest, #56129) [Link]

Yes, perhaps I should have made it more clear that C++ is also about low level programming.