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Why I don't spend time with Modern C++ anymore

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Re: Why I don't spend time with Modern C++ anymore

#11

Post by gpderetta »

pjc50 wrote: post #6

There are two separate rants here that aren't delineated well. 1) C++ is too complicated, and therefore hard to reason about and slow to compile. We're going to argue about this forever, but you'll have to agree that the spec is very large and warty compared to other languages, and that C++ tends to take far longer to compile (this was already a problem a decade ago, it's not specific to "modern" C++). 2) The future…

Can't really argue about 1.

About 2, in-order single instruction execution hasn't been an assumption for a very long time; c and c++ optimizers (and programmers) have been able to take advantage of these CPU features for a while. There are language extensions (Cilk++, OpenMP), to take advantage of extra cores for fine grained parallelism.

Regarding GPUs, arguably C and C++ have the most mature and transparent offloading support all around (OpenACC, again OpenMP, whatever MS offloading extensions are called) and the most popular GPU programming language (CUDA) is a C++ dialect.

Regarding the flat memory model, for large scale programming the only sane model is a flat, cache coherent one; those architectures that don't provide that, either evolve to provide it or die (cf. CELL) supplanted by those that do (yes, that doesn't mean that all memory is the same, but that is true with your standard CPU anyway).

I don't have an opinion on FPGAs, I expect that, if they ever go mainstream, initially people will just assemble predefined blocks via high level languages, but who knows what the future reserves us.

Re: Why I don't spend time with Modern C++ anymore

#13

Post by entelechy »

ishi wrote: post #4
fsloth wrote: post #2

This sounds like it's written from the point of view of implementing something inhouse. I fail to see how FPGA programming will be relevant if one wants to distribute software for consumers (or am I technologically clueless...).

According to the writer's LinkedIn profile, he comes from the world of High Frequency Trading. That's an area where performance is so important, that it might make sense to design your own hardware. And you certainly don't want to distribute it to anyone... I do agree with the writer that with each release, C++ has become more and more complicated, seriously hurting the maintainability of C++ code.

I also agree that c++ is getting more and more complex over time. However if you build things from scratch and you cherry pick your language features, C++ can be quite pleasant.

Re: Why I don't spend time with Modern C++ anymore

#14

Post by lmm »

kangar00 wrote: post #7

> If you cannot figure out in one minute what a C++ file is doing, assume the code is incorrect. This statement at first resonated with me, and then I thought about it: this doesn't reduce the complexity of the overall application or service, it just means that one file is simple. You could have 10,000 files instead of 1 much shorter one; is that any more simple?

Yes. If each file makes sense in isolation then the whole will as well. Just splitting code into lots of files won't necessarily produce files that you can figure out in 1 minute though (you have to define the boundaries between files such that they make sense).

Re: Why I don't spend time with Modern C++ anymore

#15

Post by daemin »

adrianN wrote: post #10
daemin wrote: post #9

Earlier quoted context omitted.

I got the feeling that the author's beef with Modern C++ is the same as for any C++ that is template heavy. And to me it is not a new or unique experience (i.e. not limited to Modern C++) to have builds that take 45 minutes to build everything. It can happen in older code and in newer code.

Yes, templates make the compiler work harder (sometimes at least), but badly modularized code with "big ball of mud" dependency structure also makes the compiler work a lot. You don't need fancy features to do that.

In my experience both have been true. That's why you get 10+ minute link times in some projects, so even if you use Incredibuild to compile, it still takes ages to link.

Re: Why I don't spend time with Modern C++ anymore

#16

Post by ensiferum »

It just sounds like someone who couldn't handle C++ whining and making a bunch of blanket statements without really having any proper understanding.

I agree that some of the features such as lambdas can use to hard to track bugs (lifetime issues) and difficult to follow code when abused. When used nicely though they can lead to simple, elegant and straightforward code (anyone who tried to use the STL algorithms before lambdas knows what a pita it was most of the time).

Bottom line, if your code base is a mess don't blame the tool. Blame the programmers.

Re: Why I don't spend time with Modern C++ anymore

#17

Post by viraptor »

kangar00 wrote: post #7

> If you cannot figure out in one minute what a C++ file is doing, assume the code is incorrect. This statement at first resonated with me, and then I thought about it: this doesn't reduce the complexity of the overall application or service, it just means that one file is simple. You could have 10,000 files instead of 1 much shorter one; is that any more simple?

Depends how well the project is structured. Imagine that you're writing a function that adds some values to a hashmap. Would you rather have the the logic, the hashing, and the datastructure details in that function? Getting a shorter function and reduced complexity in that function is great, even if it doesn't affect the complexity of the whole project.

If the modules are well-designed, you can ignore how the hashmap works and the details of hashing itself. You'll get at least 4 extra files, but yes, it's very likely worth it.

Re: Why I don't spend time with Modern C++ anymore

#19

Post by fjanisze »

lmm wrote: post #14
kangar00 wrote: post #7

> If you cannot figure out in one minute what a C++ file is doing, assume the code is incorrect. This statement at first resonated with me, and then I thought about it: this doesn't reduce the complexity of the overall application or service, it just means that one file is simple. You could have 10,000 files instead of 1 much shorter one; is that any more simple?

Yes. If each file makes sense in isolation then the whole will as well. Just splitting code into lots of files won't necessarily produce files that you can figure out in 1 minute though (you have to define the boundaries between files such that they make sense).

In my opinion this only shift the problem from coding clean code to handling hundreds or thousands of simple and small source files. This will make much more complicated to handle a large project because everything is scattered in such an extend that a developer spend more time searching thru the include list of files than understanding what the code is actually doing. Implementing complex functionality is going to be a nightmare and the end, everything is going to be merged in a single translation unit anyway. But this is just my personal opinion..

Re: Why I don't spend time with Modern C++ anymore

#20

Post by agumonkey »

kangar00 wrote: post #7

> If you cannot figure out in one minute what a C++ file is doing, assume the code is incorrect. This statement at first resonated with me, and then I thought about it: this doesn't reduce the complexity of the overall application or service, it just means that one file is simple. You could have 10,000 files instead of 1 much shorter one; is that any more simple?

Felt like this after doing lisp/python coming from Java. In the end it's about being sensible on reducing a system size, no matter where the 'unit' is.
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