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The C++ standard for the F-35 Fighter Jet [video]

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Re: The C++ standard for the F-35 Fighter Jet [video]

#151

Post by ivanjermakov »

bluecalm wrote: post #123
ivanjermakov wrote: post #71

Earlier quoted context omitted.

Zig makes it explicit with _ = a; And you would encounter it quite often because unused variable is a compilation error: https://github.com/ziglang/zig/issues/335

Doesn't it make it more likely unused variables stay in the codebase? You want to experiment, the code doesn't compile, you add this (probably by automatic tool), the code now compiles. You're happy with your experiment. As the compiler doesn't complain you commit and junk stays in the code. Isn't it just bad design that makes both experimenting harder and for unused variables to stay in the code in the final version…

It is indeed quite controversial aspect of Zig's design. I would rather prefer it be a warning. Argument "warnings are always ignored" just doesn't hold because anything can be ignored if there is a way to suppress it.

Re: The C++ standard for the F-35 Fighter Jet [video]

#152

Post by jojobas »

time4tea wrote: post #45

a = a; // misra Actual code i have seen with my own eyes. (Not in F-35 code) Its a way to avoid removing an unused parameter from a method. Unused parameters are disallowed, but this is fine? I am sceptical that these coding standards make for good code!

Isn't it inevitable for some cases of inheritance? A superclass does something basic and doesn't need all parameters, child classes require additional ones.

Re: The C++ standard for the F-35 Fighter Jet [video]

#153

Post by throwaway2037 »

uecker wrote: post #132
EliRivers wrote: post #69

Earlier quoted context omitted.

I worked on the same for many years; same deal - playout system for broadcast, years of uptime, never miss a frame. The C++ was atrocious. Home-made reference counting that was thread-dangerous, but depending on what kind of object the multi-multi-multi diamond inheritance would use, sometimes it would increment, sometimes it wouldn't. Entire objects made out of weird inheritance chains. Even the naming system was cr…

A multi-inhertiance system is certainly not something somebody who "was thinking in C" would ever come up with. This sounds more like a true C++ mess.

I worked on a pure C system early in my career. They implemented multiple inheritance (a bit like Perl/Python MRO style) in pure C. It was nuts, but they didn't abuse it, so it worked OK.

Also, serious question: Are they any GUI toolkits that do not use multiple inheritance? Even Java Swing uses multiple inheritance through interfaces. (I guess DotNet does something similar.) Qt has it all over the place.

Re: The C++ standard for the F-35 Fighter Jet [video]

#154

Post by jasonwatkinspdx »

throwaway2037 wrote: post #146
riku_iki wrote: post #143

Earlier quoted context omitted.

what would be so obviously better choice of language in your opinion?

You raise a good point. No trolling: I wonder what languages they seriously considered? Example: I am sure the analysis included C in the mix. Also, I wonder if they considered compiler extensions. Example: Since C doesn't have destructors, maybe you could add a compiler extension to add the defer keyword to allow people to schedule object destruction. Even when they decided upon C++, I am sure there was a small holy…

Ada and C++ were the only realistic options at the time, and Ada developers are difficult to hire.

But honestly, with this sort of programming the language distinctions matter less. As the guide shows you restrict yourself to a subset of the language where distinctions between languages aren't as meaningful. Basically everything runs out of statically allocated global variables and arrays. Don't have to worry about fragmentation and garbage collection if there's no allocation at all. Basically remove any source of variability in execution possible.

So really you could do this in any c style language that gives you control over the memory layout.

Re: The C++ standard for the F-35 Fighter Jet [video]

#155

Post by nottorp »

throwaway2037 wrote: post #153
uecker wrote: post #132

Earlier quoted context omitted.

A multi-inhertiance system is certainly not something somebody who "was thinking in C" would ever come up with. This sounds more like a true C++ mess.

I worked on a pure C system early in my career. They implemented multiple inheritance (a bit like Perl/Python MRO style) in pure C. It was nuts, but they didn't abuse it, so it worked OK. Also, serious question: Are they any GUI toolkits that do not use multiple inheritance? Even Java Swing uses multiple inheritance through interfaces. (I guess DotNet does something similar.) Qt has it all over the place.

One could say toolkits done in C++ use multiple inheritance because C++ doesn't have interfaces though.

Re: The C++ standard for the F-35 Fighter Jet [video]

#156

Post by hu3 »

fl7305 wrote: post #134
tsunagatta wrote: post #122

Earlier quoted context omitted.

The F-35 was in development hell for a while for sure, but it’s far from a failure. See the recent deals where it’s been used as a political bargaining chip; it still ended up being a very desirable and capable platform from my understanding.

> See the recent deals where it’s been used as a political bargaining chip; it still ended up being a very desirable and capable platform from my understanding. From a european perspective, I can tell you that the mood has shifted 180 degrees from "buy American fighters to solidify our ties with the US" to "can't rely on the US for anything which we'll need when the war comes" .

that has nothing to do with the F-35.

Europe is wise and capable enough to develop their own platform.

Re: The C++ standard for the F-35 Fighter Jet [video]

#157

Post by jasonwatkinspdx »

factorialboy wrote: post #110

Isn't the F35 program considered a failure? Or am I confusing it with some other program?

There's a ton of absolutely garbage reporting on it. No like seriously a ton of the articles are just more mainstream media uncritically reposting claims by a couple cranks in Australia that LARP as a think tank.

Anyhow, a fair assessment is the program has gone massively over timeline and budget, so in that sense is a failure, however the resulting aircraft is very clearly the best in its class both in absolute capability and value.

Going forward there's broad awareness in the government that the program management mistakes of the F-35 program cannot be repeated. There's a general consensus that 3 decade long development projects just won't be relevant in a world where drone concepts and similar are evolving rapidly on a year by year basis. There's also awareness the government needs to act more as the integrator that owns the project to avoid lock in issues.

Re: The C++ standard for the F-35 Fighter Jet [video]

#158

Post by MobiusHorizons »

jjmarr wrote: post #140
time4tea wrote: post #45

a = a; // misra Actual code i have seen with my own eyes. (Not in F-35 code) Its a way to avoid removing an unused parameter from a method. Unused parameters are disallowed, but this is fine? I am sceptical that these coding standards make for good code!

An unused parameter should be commented out.

Unless it’s there to conform to an interface

Re: The C++ standard for the F-35 Fighter Jet [video]

#159

Post by Animats »

jandrewrogers wrote: post #8

For those interested, the F-35 (née Joint Strike Fighter) C++ coding standards can be found here, all 142 pages of it: https://www.stroustrup.com/JSF-AV-rules.pdf

As is common in hard real time code, there is no dynamic allocation during operation:

    allocation/deallocation from/to the free store (heap) 
    shall not occur after initialization.
This works fine when the problem is roughly constant, as it was in, say, 2005. But what do things look like in modern AI-guided drones?

Re: The C++ standard for the F-35 Fighter Jet [video]

#160

Post by binary132 »

binary132 wrote: post #94
time4tea wrote: post #45

a = a; // misra Actual code i have seen with my own eyes. (Not in F-35 code) Its a way to avoid removing an unused parameter from a method. Unused parameters are disallowed, but this is fine? I am sceptical that these coding standards make for good code!

It’s very weird how none of the sibling comments understood what it were saying is wrong with this.

Erm, sorry about the weird typo. Didn’t notice. Can’t edit now.
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