21–30 of 140 posts
I'm going to be the first to point out the one major flaw in this comparison: "plain C using GLib" is not comparable to "C++ standard library only" --- what should be compared is "C++ standard library only" and "C standard library only". Reimplementing pkg-config in pure C without GLib would be necessary for that. As for the "memory leaks" --- I haven't looked at the source, but something whose runtime is very short-…
> My experience has been the complete opposite. Keyword: "can".
I'm going to be the first to point out the one major flaw in this comparison: "plain C using GLib" is not comparable to "C++ standard library only" --- what should be compared is "C++ standard library only" and "C standard library only". Reimplementing pkg-config in pure C without GLib would be necessary for that. As for the "memory leaks" --- I haven't looked at the source, but something whose runtime is very short-…
To be fair in the other direction, it's a minority of interesting software projects that don't care about memory leaks. Also, there are ways to "skip" freeing memory in C++ safely using appropriate allocators. In actuality, you'd have your allocator, in its destructor, clean up itself and all its objects at the same time. It's nearly the same performance without sacrificing correctness or lowering standards with respect to leaking memory.
I'm going to be the first to point out the one major flaw in this comparison: "plain C using GLib" is not comparable to "C++ standard library only" --- what should be compared is "C++ standard library only" and "C standard library only". Reimplementing pkg-config in pure C without GLib would be necessary for that. As for the "memory leaks" --- I haven't looked at the source, but something whose runtime is very short-…
But sometimes the code grows and what was once a stand-alone executable is about to become a component in a larger executable. With C++ you get a correct component out of the box (if you use RAII consistently), but with C you have to audit all of the code and clean up the leaks.
If you ignore the protection mechanisms and the class heirarchy built into C++, then a C++ class is like a C struct that can contain function pointers. For many programs this is all that's needed, and the amount of overhead involved in using such an approach to creating objects is obviously lower. So there's no question C will always be faster. It's only when you need protection and class heirarchies that C++ benefit…
Well, need is a strong word. You might not need better correctness while still coming out way ahead by using C++.
according to dan saks, who apparently to some people is famous c++ is faster than c (well in the test setup he describes below) https://accu.org/content/conf2015/DanSaks-Embedded%20Program... Language Design Implementation Relative Performance either any inline 1 (fastest) C++ polystate non-inline 1.56 x fastest C++ bundled non-inline 1.65 x fastest C polystate non-inline 1.70 x fastest C bundled non-inline 1.79 x fa…
> "if you're using C++ as a better C you're doing it wrong" As far as correctness and safety goes, this is still true. It's difficult to scale systems-level programming to large teams. C++ gives the opportunity for more explicit semantics and more aggressive compile-time checks. C can scale well and can be used safely, but you need to do a lot more through convention (always call xyz_Create and xyz_Destroy in pairs!)…
Some of the structural advantages of C++ over C can be achieved in C by using generative programming for example and building in automatic mechanisms to ensure there are no memory leaks for example. In other words, the C++ approach to structuring programs is not the only way to achieve the benefits that that structuring implies. It's just really easy to do it that way.
I'm going to be the first to point out the one major flaw in this comparison: "plain C using GLib" is not comparable to "C++ standard library only" --- what should be compared is "C++ standard library only" and "C standard library only". Reimplementing pkg-config in pure C without GLib would be necessary for that. As for the "memory leaks" --- I haven't looked at the source, but something whose runtime is very short-…
Reminds me of this anecdote I came across on the internets one time: https://groups.google.com/forum/message/raw?msg=comp.lang.ad...
You can't compare performance If one program doesn't free memory, which obviously "saves" time. Valgrind can tell you where non-freed heap blocks have been allocated and a fix should not be complicated.
Earlier quoted context omitted.
Reminds me of this anecdote I came across on the internets one time: https://groups.google.com/forum/message/raw?msg=comp.lang.ad...
The ultimate in garbage collection indeed! Highly recommend reading that short tale! This lore is slowly being forgotten, thanks for that link.
(Is there a canonical lore repository for this kind of thing, other than the Jargon file?)
I'm going to be the first to point out the one major flaw in this comparison: "plain C using GLib" is not comparable to "C++ standard library only" --- what should be compared is "C++ standard library only" and "C standard library only". Reimplementing pkg-config in pure C without GLib would be necessary for that. As for the "memory leaks" --- I haven't looked at the source, but something whose runtime is very short-…
Earlier quoted context omitted.
Or take that even further and allocate a slab that's big enough to last the entire runtime and send malloc on vacation. It's worth repeating, with todays focus on web-frameworks, cloud-providers and dogmatics these ideas are slipping into obscurity; which is a shame given how beneficial they can be if your program fits the use case.
And, instead of using pointers into said memory, use indices so that the slab can be reallocated, or just mmap more pages following the slab if you own the process address space. Also, align properly. And having guard pages is always nice. Freeing on exit too, one single deallocation is pretty cheap. I've seen programs building ASTs with hundreds of millions of nodes, where all the nodes were allocated by a separate…
Last time I did any serious parser work I used a pool allocator so I could free all the nodes at once, so allocation was just a compare + increment operation. Although that was forced on me by the difficulties of error recovery in yacc.