[fpoling]

The article over-downplays the need for sentinel values. Surely Rust has Option that also spreads into C++ these days as std::optional. But for plain C using -1 or negative values to denote sentinels or error code is rather nice idiom.

The argument will be more valid if array indexes will be 1-based like in Fortran/Matlab/Julia as then 0 becomes extremely nice sentinel values. But C is C and needs -1.

[rstuart4133]

Not disagreeing about the need for sentinel values, but Rust also has NonZero. When combined with Option, you get a similar result to outcome to C's -1.

Similar because it's a compiler hack, as in the compiler treats std::num::NonZero specially. You can't create your own type with the same properties as you can in C.