I've worked on a playout system for broadcast television. The software has to run for years at a time and not have any leaks, We need to send out one frame of television exactly on time, every time.

It is "C++", but we also follow the same standards. Static memory allocation, no exceptions, no recursion. We don't use templates. We barely use inheritance. It's more like C with classes.

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EliRivers a day ago | parent [-]

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 crazy; "pencilFactory" wasn't a factory for making pencils, it was anything that was made by the factory for pencils. Inheritance rather than composition was very clearly the model; if some other object had function you needed, you would inherit from that also. Which led to some object inheriting from the same class a half-dozen times in all.

The multi-inheritance system given weird control by objects on creation defining what kind of objects (from the set of all kinds that they actually were) they could be cast to via a special function, but any time someone wanted one that wasn't on that list they'd just cast to it using C++ anyway. You had to cast, because the functions were all deliberately private - to force you to cast. But not how C++ would expect you to cast, oh no!

Crazy, home made containers that were like Win32 opaque objects; you'd just get a void pointer to the object you wanted, and to get the next one pass that void pointer back in. Obviously trying to copy MS COM with IUnknown and other such home made QueryInterface nonsense, in effect creating their own inheritance system on top of C++.

What I really learned is that it's possible to create systems that maintain years of uptime and keep their frame accuracy even with the most atrocious, utterly insane architecture decisions that make it so clear the original architect was thinking in C the whole time and using C++ to build his own terrible implementation of C++, and THAT'S what he wrote it all in.

Gosh, this was a fun walk down memory lane.

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uecker a day ago | parent | next [-]

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.

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throwaway2037 a day ago | parent [-]

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.

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aninteger a day ago | parent | next [-]

The best example I can think of is the Win32 controls UI (user32/Create window/RegisterClass) in C. You likely can't read the source code for this but you can see how Wine did it or Wine alternatives (like NetBSD's PEACE runtime, now abandoned).

Actually the only toolkit that I know that sort of copied this style is Nakst's Luigi toolkit (also in C).

Neither really used inheritance and use composition with "message passing" sent to different controls.

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uecker 15 hours ago | parent | prev | next [-]

I take this back ;-) People come up with crazy things. Still I would not call this "C thinking". Building object-oriented code in C is common though and works nicely.

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nottorp a day ago | parent | prev | next [-]

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

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WD-42 a day ago | parent | prev [-]

GTK does not support multiple inheritance afaik.

	▲	aninteger 21 hours ago \| parent [-]
		It doesn't but it definitely "implements" a single inheritance tree (with up casting/down casting) which I believe Xt toolkits (like Motif) also did.

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webdevver a day ago | parent | prev [-]

it is also interesting that places where you would expect to have quite 'switched-on' software development practices tend to be the opposite - and the much-maligned 'codemonkeys' at 'big tech' infact tend to be pretty damn good.

it was painful for me to accept that the most elite programmers i have ever encountered were the ones working in high frequency trading, finance, and mass-producers of 'slop' (adtech, etc.)

i still ache to work in embedded fields, in 8kB constrained environment to write perfectly correct code without a cycle wasted, but i know from (others) experience that embedded software tends to have the worst software developers and software development practices of them all.