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Or passing by value vs passing a pointer, or the importance of memory management... Modern languages solve problems created developing in legacy languages (pri

Or passing by value vs passing a pointer, or the importance of memory management... Modern languages solve problems created developing in legacy languages (primarily C). The issue is that knowing a solution without knowing the prior problem which the solution addresses, doesn't really lend itself to clarity.

Sir_Cmpwn 8y ago
They don't solve problems created by C, they just solve problems C doesn't. The problems still exist, and sometimes the high-level compiler even picks the wrong solution. Learning C helps you understand when and why this has happened.
- flyinglizard 8y ago
  Arguably those problems did not exist before the C-era as software wasn't large or complicated enough. C++ directly attempts to improve over C by providing new mechanisms to solve problems encountered by C developers every day. Point is that out of context, a lot of the things modern languages provide seem superfluous. Why have objects? Why have templates, closures, or lambdas? For a novice programmer, these are many answers for questions yet to be asked. When you come from a heavy C background and you encounter something like templates, you know EXACTLY what this is for and wish you had it years ago. I'm as hardcore as they get C programmer and I'm having a ball with C# for this very reason.
  - Sir_Cmpwn 8y ago
    When I see templates, I run in the opposite direction at a dead sprint. C++ has added very little of value to the language and templates are one of their worst offerings. Metaprogramming is an antipattern in C.
    - sevensor 8y ago
      > Metaprogramming is an antipattern in C. Yet we often see passionate arguments in its favor, as for instance from Sústrik (http://250bpm.com/blog:56 http://250bpm.com/blog:56) and Tatham (https://www.chiark.greenend.org.uk/~sgtatham/mp/ https://www.chiark.greenend.org.uk/~sgtatham/mp/) and a person on the internet who recommends replacing LAPACK with preprocessor macros (http://wordsandbuttons.online/outperforming_lapack_with_c_metaprogramming.html http://wordsandbuttons.online/outperforming_lapack_with_c_me...). Would you care to comment on its enduring popularity?
      - Sir_Cmpwn 8y ago
        You can write bad code in any language, C is no exception. We also see people persistently arguing in favor of simpler and less magical C. If you want reliable, maintainable code in any language, do not use magic. Metaprogramming is cool, no doubt about it, but it's unnecessary and creates bad code.
- lmm 8y ago
  "Exploding" undefined behaviour is a problem created by C. Other languages don't have it, not even assembly languages.
  - steveklabnik 8y ago
    There are many languages which have undefined behavior. C does have a lot of it, and it can be anywhere. In many languages, you can cause undefined behavior through its FFI. Some languages, like Rust, have UB, but only in well-defined places (a module containing unsafe code, in its case).
    - lmm 8y ago
      If a language lets you cause undefined behaviour via FFI into C, I think it's fair to say that that remains a problem created by C. I do take your point about Rust, but I'd see that as deriving from LLVM's undefined behaviour which in turn descends from C; I'm not aware of any pre-C languages having C-style exploding undefined behaviour or of any subsequent languages inventing it independently.
      - steveklabnik 8y ago
        > I think it's fair to say that that remains a problem created by C. That is fair, however, I don't think it's inherently due to C. Yes, most languages use the C ABI for FFI, but that doesn't mean they have to; it's a more general problem when combining two systems, they cannot track statically the guarantees of the other system. With Rust, it has nothing to do with LLVM; it has to do with the fact that we cannot track things, that's why it's unsafe! Even if an implementation of the language does not use LLVM, we will still have UB.
        lmm 8y ago
        > With Rust, it has nothing to do with LLVM; it has to do with the fact that we cannot track things, that's why it's unsafe! Even if an implementation of the language does not use LLVM, we will still have UB. I can see that any implementation of unsafe Rust would always have assembly-like unsafeness (e.g. reading an arbitrary memory address might result in an arbitrary value, or segfault). But I don't see why you would need C-style "arbitrary lines before and after the line that will not execute, reads from unrelated memory addresses will return arbitrary values" UB?
sephoric 8y ago
Memory management in C is very different than memory management in JavaScript, which throws exceptions when you try to access invalid memory, but will gladly let you create memory leaks inside event callbacks or other loops and keep chugging along gladly until it can't anymore. Writing a safe, efficient, high performing JavaScript app is very different than writing the same thing in C, and although I know both deeply well, I don't think learning C has helped me write better JS.
oleganza 8y ago
After recently (1 year) learning Rust I noticed that Rust teaches about low-level CS concepts of passing by value vs passing by pointer a lot better than C. Because you not just have references and values, but also have to think about richer semantics of what you are trying to do: sharing, mutability, and move semantics. So you learn not only that a few low level concepts exist, but you also learn how to use them correctly.

Sir_Cmpwn 8y ago

They don't solve problems created by C, they just solve problems C doesn't. The problems still exist, and sometimes the high-level compiler even picks the wrong solution. Learning C helps you understand when and why this has happened.

flyinglizard 8y ago
Arguably those problems did not exist before the C-era as software wasn't large or complicated enough. C++ directly attempts to improve over C by providing new mechanisms to solve problems encountered by C developers every day. Point is that out of context, a lot of the things modern languages provide seem superfluous. Why have objects? Why have templates, closures, or lambdas? For a novice programmer, these are many answers for questions yet to be asked. When you come from a heavy C background and you encounter something like templates, you know EXACTLY what this is for and wish you had it years ago. I'm as hardcore as they get C programmer and I'm having a ball with C# for this very reason.
- Sir_Cmpwn 8y ago
  When I see templates, I run in the opposite direction at a dead sprint. C++ has added very little of value to the language and templates are one of their worst offerings. Metaprogramming is an antipattern in C.
  - sevensor 8y ago
    > Metaprogramming is an antipattern in C. Yet we often see passionate arguments in its favor, as for instance from Sústrik (http://250bpm.com/blog:56 http://250bpm.com/blog:56) and Tatham (https://www.chiark.greenend.org.uk/~sgtatham/mp/ https://www.chiark.greenend.org.uk/~sgtatham/mp/) and a person on the internet who recommends replacing LAPACK with preprocessor macros (http://wordsandbuttons.online/outperforming_lapack_with_c_metaprogramming.html http://wordsandbuttons.online/outperforming_lapack_with_c_me...). Would you care to comment on its enduring popularity?
    - Sir_Cmpwn 8y ago
      You can write bad code in any language, C is no exception. We also see people persistently arguing in favor of simpler and less magical C. If you want reliable, maintainable code in any language, do not use magic. Metaprogramming is cool, no doubt about it, but it's unnecessary and creates bad code.
lmm 8y ago
"Exploding" undefined behaviour is a problem created by C. Other languages don't have it, not even assembly languages.
- steveklabnik 8y ago
  There are many languages which have undefined behavior. C does have a lot of it, and it can be anywhere. In many languages, you can cause undefined behavior through its FFI. Some languages, like Rust, have UB, but only in well-defined places (a module containing unsafe code, in its case).
  - lmm 8y ago
    If a language lets you cause undefined behaviour via FFI into C, I think it's fair to say that that remains a problem created by C. I do take your point about Rust, but I'd see that as deriving from LLVM's undefined behaviour which in turn descends from C; I'm not aware of any pre-C languages having C-style exploding undefined behaviour or of any subsequent languages inventing it independently.
    - steveklabnik 8y ago
      > I think it's fair to say that that remains a problem created by C. That is fair, however, I don't think it's inherently due to C. Yes, most languages use the C ABI for FFI, but that doesn't mean they have to; it's a more general problem when combining two systems, they cannot track statically the guarantees of the other system. With Rust, it has nothing to do with LLVM; it has to do with the fact that we cannot track things, that's why it's unsafe! Even if an implementation of the language does not use LLVM, we will still have UB.
      - lmm 8y ago
        > With Rust, it has nothing to do with LLVM; it has to do with the fact that we cannot track things, that's why it's unsafe! Even if an implementation of the language does not use LLVM, we will still have UB. I can see that any implementation of unsafe Rust would always have assembly-like unsafeness (e.g. reading an arbitrary memory address might result in an arbitrary value, or segfault). But I don't see why you would need C-style "arbitrary lines before and after the line that will not execute, reads from unrelated memory addresses will return arbitrary values" UB?

sephoric 8y ago

Memory management in C is very different than memory management in JavaScript, which throws exceptions when you try to access invalid memory, but will gladly let you create memory leaks inside event callbacks or other loops and keep chugging along gladly until it can't anymore. Writing a safe, efficient, high performing JavaScript app is very different than writing the same thing in C, and although I know both deeply well, I don't think learning C has helped me write better JS.

oleganza 8y ago

After recently (1 year) learning Rust I noticed that Rust teaches about low-level CS concepts of passing by value vs passing by pointer a lot better than C. Because you not just have references and values, but also have to think about richer semantics of what you are trying to do: sharing, mutability, and move semantics. So you learn not only that a few low level concepts exist, but you also learn how to use them correctly.