7 ms·

What's the reason for ffmpeg to use C, also historic?

• defrost 2y ago
  Fabrice also wrote the Tiny C compiler, so very much his language of choice .. For those used to the language it was seen as "lighter" and easier to add OO like abstractions to your C usage than bog down in the weight and inconsistencies of (early) C++ https://bellard.org/ https://bellard.org/ https://en.wikipedia.org/wiki/Fabrice_Bellard https://en.wikipedia.org/wiki/Fabrice_Bellard
  • lelanthran 2y ago
    > weight and inconsistencies of (early) C++ Since very little is ever removed from C++, all the inconsistencies in C++ are still there.
    • maccard 2y ago
      Every language has inconsistencies, and C is not stranger to that. Much of c++’s baggage is due to C and you carry the same weight. That’s not to say that initialization isn’t broken in C++, but just like many features in many languages (off the top of my head in C - strcpy, sprintf, ctime are like hand grenades with the pin pre pulled for you) don’t use them. There’s a subset of C++17 that to me solves so many issues with C and C++ that it just makes sense to use. An example from a codebase I spend a lot of time in is int val; bool valueSet = getFoo(&val); if (valueSet) {} printf(“%d”, val); // oops The bug can be avoided entirely with C++ if (int val; getFoo(&val)) // if you control getFoo this could be a reference which makes the null check in getFoo a compile time check {} printf(“%d”, val); // this doesn’t compile.
      • ablob 2y ago
        You could write this in C, no? { int val; if (getFoo(&val)) { ... }} Both ways of expressing this are weird, but stating that this can't be achieved with C is dishonest in my opinion.
        • i_am_a_peasant 2y ago
          it's not that weird to explicitly limit the scope of certain variables that logically belong together. But i agree the C++ if(init;cond) thing was new to me.
          • maccard 2y ago
            Like everything in C++, it has it's share of footguns if (Foo* f = GetPtr(); f->HasValue()) {} // wrong; f can be null vs if (Foo* f = GetPtr(); f && f->HasValue()){} Is probably the biggest pitfall. Especially if you're used to this: if (Foo* f = GetPtr()) { f->DoTheThing(); // this is perfectly safe. }
        • maccard 2y ago
          If I reformat this, { int val; if (getFoo(&val)) { } printf("%d", val); } The bug is still possible, as you've introduced an extra scope that doesn't exist in the C++ version. Also, this was one example. There are plenty of other examples.
      • ho_schi 2y ago
        For C users. And C++ users: In C++ we can declare variable in the while or if statement: https://en.cppreference.com/w/cpp/language/while https://en.cppreference.com/w/cpp/language/while https://en.cppreference.com/w/cpp/language/if https://en.cppreference.com/w/cpp/language/if It's value is the value of the decision. This is not possible with C [1]. Since C++17 the if condition can contain an initializer: Ctrl+F if statements with initializer https://en.cppreference.com/w/cpp/language/if https://en.cppreference.com/w/cpp/language/if Which sounds like the same? Now you can declare a variable and it value is not directly evaluated, you also can compare it in a condition. I think both are neat features of C++, without adding complexity. [1] Also not possible with Java.
        • trelane 2y ago
          Declaring a variable in a loop or if statement is supported since C99: https://en.wikipedia.org/wiki/C99 https://en.wikipedia.org/wiki/C99 Also in Java: https://www.geeksforgeeks.org/for-loop-java-important-points/ https://www.geeksforgeeks.org/for-loop-java-important-points...
          • maccard 2y ago
            No, declaring a variable in a `for` loop is supported in C99 but you can't do if-init.
            • trelane 2y ago
              Ah, you're right (finally tried it out). But it 100% works in a loop (usually for loop)
              • maccard 2y ago
                It’s one of those things that I never knew I wanted until I started using it, and now i miss it when it’s not available.The reason you want it is the same reason you want to declare a variable in the statement of a for loop rather than pre declaring and using a while loop
      • tialaramex 2y ago
        Variables like "valueSet" scream out that the language lacks a Maybe type instead. One of the worst things about C++ is that it's content to basically not bother improving on the C type system.
        • rowanG077 2y ago
          C++ has a maybe type. It's called std::optional.
          • uecker 2y ago
            Here is my experimental maybe type for C: https://godbolt.org/z/YxnsY7Ted https://godbolt.org/z/YxnsY7Ted
            • tialaramex 2y ago
              Six divided by minus one is a "Division by zero" now? Where I come from that's minus six. Good luck to WG14 (or maybe a faction within it?) as they seem to have decided to go make their own C++ competitor now, it's a weird time to do that, but everybody needs a hobby.
              • uecker 2y ago
                Yeah, I was about to add the test for INT_MIN / -1 but got distracted, but also not really the point of the example anyway. I hope you realize that this is example does not need any complex C++ features.
                • tialaramex 2y ago
                  I mean, sure. I read the "noplate" code. Did you ever watch the Mrs Merton show? "So, what first attracted you to the millionaire Paul Daniels?". There's a reason you felt the need to insist that your C language generic containers aren't relying on "complex C++ features" whatever you might decide that means.
      • uecker 2y ago
        This will be in C2Y and is already supported by GCC 15: https://godbolt.org/z/szb5bovxq https://godbolt.org/z/szb5bovxq
        • maccard 2y ago
          This is one example. Off the top of my head std.array vs "naked" C arrays, string vs const char*, and let's not forget RAII are all features that just make me never want to work with vanilla C ever again.
          • uecker 2y ago
            For me, std.array seem fundamentally inferior compared to C arrays. A good standard string type is indeed missing, but it is also easy to define one. RAII, I can see, but I also some advantages to have explicit resource deallocation visible in the code and it is not really bothering me too much to write this explicitly.
• emmelaich 2y ago
  Much easier to link / load into other language binaries surely.
  • adastra22 2y ago
    extern “C” works just fine.
    • josefx 2y ago
      Only if your entire API doesn't contain any C++.
      • pjmlp 2y ago
        C is also C++, at least the C89 subset.
        • procaryote 2y ago
          it actually isn't https://www.stroustrup.com/bs_faq.html#C-is-subset https://www.stroustrup.com/bs_faq.html#C-is-subset
          • pjmlp 2y ago
            Do you usually post links without reading them? "In the strict mathematical sense, C isn't a subset of C++. There are programs that are valid C but not valid C++ and even a few ways of writing code that has a different meaning in C and C++. However, C++ supports every programming technique supported by C. Every C program can be written in essentially the same way in C++ with the same run-time and space efficiency. It is not uncommon to be able to convert tens of thousands of lines of ANSI C to C-style C++ in a few hours. Thus, C++ is as much a superset of ANSI C as ANSI C is a superset of K&R C and much as ISO C++ is a superset of C++ as it existed in 1985. Well written C tends to be legal C++ also. For example, every example in Kernighan & Ritchie: "The C Programming Language (2nd Edition)" is also a C++ program. "
• layer8 2y ago
  C has less moving parts — it’s more difficult to define a subset of C++ that actually works across all platforms featuring a C++ compiler, not to mention of all the binary-incompatible versions of the C++ standard library that tend to exist — and C is supported on a wider variety of platforms. If you want to maximize portability, C is the way to go, and you run into much fewer problems.