• pinknoise
    6·
    3 years ago

    Fun fact: the C standard neither defines the size nor the signedness of char.

    Also the rust side is missing Vec<char> and maybe Chars<'_> and I’m sure you can make up more representations :D

    Also there is at least also wchar_t* on the C side because you can’t (always) cast between the two. (I mean you can, but you shouldn’t)

    • pinknoise
      4·
      3 years ago

      I feel bad because I immediately knew what the abbreviations stand for -.-

      wchar_t isn’t from win32, but from ISO C. There should be a compatibility typedef/define called WCHAR in win32 headers for compilers that don’t have wchar_t.

  • ghost_laptop
    21·
    3 years ago

    All those are ways of calling string in C? Why are there so many?

    • nachtigall@feddit.de
      9·
      3 years ago

      The primary reason there are so many ways is the Rust ownership and type system.

      • String is a ‘normal’ mutable UTF-8 string that is allocated on the heap.
      • &str is either a slice reference pointing to a part of a string or a string literal in read-only memory.
      • &[u8] is a reference to slice of bytes (so only capable of ASCII characters).
      • &[u8; N] is a reference to a fixed size slice reference of bytes where the length is encoded in the type.
      • Vec<u8> is a mutable array of bytes (the former two are immutable in contrast).
      • &u8 is a reference to a single byte.
      • OsString is an owned, mutable platform native string in the platform’s preferred representation (e.g. non-zero byte UTF-8 on Linux, non-zero byte UTF-16 in Windows).
      • OsStr is a borrowed version of an OsString.
      • Path is a slice that supports operations like obtaining the root element or file name or check if it is absolute or relative or to check if the the file exists in the file system.
      • PathBuf is an owned, mutable version of the former one.
      • CString is an owned representation of a string that should be compatible with C (e.g. null terminated and no zero bytes in between). They are handy if you want to call C libraries from Rust code.
      • CStr is a borrowed version of CString.
      • &'static str is a string slice reference with a static lifetime and is therefore valid for the duration of the entire program (in contrast to slices of Strings that might get de-allocated at some point).
      • Ephera
        4·
        3 years ago

        &u8 is a reference to a single byte.

        I’m not sure this meme really cares to make perfect sense, but I don’t think that’s ever useful…?

        A single byte is going to be smaller than a pointer address, so you can just copy the u8 without loss of efficiency.

    • gun
      4·
      3 years ago

      In Rust, and I don’t know

        • Ephera
          6·
          3 years ago

          The String vs. &str split is definitely annoying, but a necessary drawback of Rust’s ownership mechanics (which bring many benefits compared to C in other places).

          The others have their specific use-cases (like file paths or C interop). It’s certainly not like you constantly juggle 8 different kinds of strings.

        • gun
          3·
          3 years ago

          I don’t know, I don’t use Rust

        • jet@hackertalks.comEnglish
          2·
          1 year ago

          Not necessarily a bad thing. If your method of invocation gives context about its possible use cases. You can make the program more safe because you know it’s being used appropriately. If you’re just passing a pointer around anything could happen to it. So it’s hard to help the programmer not make mistakes