Python is memory safe? Can’t you access/address memory with C bindings?

  • Traister101@lemmy.today
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    8 months ago

    Yes Rust is harder to write than C, that’s basically by design as it’s due to the statically guaranteed memory safety. That’s pretty magical. C doesn’t have that and neither does C++ even with smart pointers and such. Rusts unsafe keyword is poorly named, what it actually does is tell the compiler that you the programmer guarantee Rusts rules are upheld within the unsafe block.

    For example

    Access or modify a mutable static variable

    That is a global, that’s incredibly hard to impossible to statically prove it’s safely done, so you have to do it in an unsafe block. So you violating Rusts rules within an unsafe block is actually using the unsafe block wrong. That’s not what it’s for

    • Solemarc@lemmy.world
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      8 months ago

      I remember watching a video of someone writing C code and making the same thing in unsafe rust. While the C code worked just fine the rust code had UB in it and was compiled to a different set of instructions.

      Unsafe rust expects you to uphold the same guarantees that normal rust does and so the compiler will make all the same optimisations it would if the code wasn’t unsafe and this caused UB in the example rust code when optimised for performance. It worked just fine on the debug build, but that’s UB for you.