Rust Result In C. Key Difference of Rust and C. The compiler enforces the rules so that there is zero runtime cost over the equivalent and correctly written program in C or C.
CXX safe FFI between Rust and C. If you do write that in Rust the compiler will give you a warning by default controlled by the unused_must_use lint. Another example is the one on the Box page which exposes the Rust standard librarys stdfsFile to C as an opaque type in a similar way but with Box as the indirection rather than mut.
Note that the return type written inside of cxxbridge must be written without a second type parameter.
If an overflow occurs C will jump to the ud2 instruction which leads to Illegal instruction core dumped while Rust jumps to the call of the corepanickingpanic function. Haskell や Rust など多くの強力な型システムを持つプログラミング言語はEither とか Result といった失敗するかもしれない計算の値を示す型を持っています 現在の C の標準ライブラリにはこのような型はありませんのでそれを自作してみようというわけです. If you make a mistake in C your program will technically have no meaning which can result in arbitrary behavior. Functions return Result whenever errors are expected and recoverable.