Comment by adrianN

2 days ago

I guess this is where the culture around rust shines. You can write crypt that returns a string in rust just fine, just like you can write crypt that returns a tagged union in C. Cultural differences and syntactic sugar change which version is idiomatic.

I suppose if people started writing lots of code that crashed on error in Rust some enterprising developer might improve the function to always return a non-error value and set it to ‘*’ in error cases.

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adrianN

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mort96  2 days ago

The culture is downstream of the design IMO. In general, people write the API that is obvious. In C, returning a string is obvious, while defining a custom OptionalString type is high friction. In Rust, returning Option<String> is as easy and obvious as returning a String.

  • asveikau  2 days ago

    In a C function returning a string, two or three idioms are common for signalling an error.

    One is to return NULL for errors.

    Another is to make the string result a parameter and use a return code to signal error.

    A third, less common but still out there, is an error parameter.

    Failure to observe these is on the caller. Forcing the caller to consider the error is probably where rust shines.

    But a good C programmer is thinking about these idioms when they encounter a function signature for the first time, or they write one.

mahboi  2 days ago

All the standard Rust libs use results. The standard C libs use errno, return 0, return -1, return EOF, return nullptr, segfault, or of course UB. Other libs dream up things like returning "*". C++ has exceptions in some areas but not others, and if you turn them off, they're segfaults. I actually like C, at least more than C++, but the error handling is the worst part.

dabinat  2 days ago

Sure, you could write deliberately bad code in Rust by unwrapping everything everywhere, but the point is that it is a distinct choice to do so. You can’t forget to handle errors - you have to make the choice to disregard them. If you forget to check for NULL in C it won’t complain and it’s dependent upon you to remember to do so.