Moving the kernel to modern C [LWN.net]

Moving the kernel to modern C

Posted Feb 26, 2022 22:10 UTC (Sat) by camhusmj38 (subscriber, #99234)
In reply to: Moving the kernel to modern C by Wol
Parent article: Moving the kernel to modern C

Type Inference is not the same as no declaration. Type Inference just means types don’t have to be explicitly stated where the compiler can infer it from the expression used to initialise the variable.

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Moving the kernel to modern C

Posted Feb 27, 2022 16:04 UTC (Sun) by marcH (subscriber, #57642) [Link] (3 responses)

Why would be the purpose of a declaration without an explicit type?

How would a typeless declaration help the people in this thread who complain about not finding declarations? If not the type, what else are they looking for?

Moving the kernel to modern C

Posted Feb 27, 2022 18:55 UTC (Sun) by camhusmj38 (subscriber, #99234) [Link] (1 responses)

The declaration has a type - it’s inferred from the initialiser. It’s really only appropriate with local variables.

Moving the kernel to modern C

Posted Feb 27, 2022 20:49 UTC (Sun) by marcH (subscriber, #57642) [Link]

I see nothing factually wrong in your last two comments above but I really don't understand why they're posted as replies to mine. I'm afraid you're misunderstanding my points and questions.

Moving the kernel to modern C

Posted Feb 27, 2022 19:06 UTC (Sun) by mathstuf (subscriber, #69389) [Link]

In Rust, it can move the lifetime of a variable around. So if I have some code that needs to live for the outer scope, but is only "known" in some nested place, I can use `let somename;` on a block in the right place, initialize it where the data is available, and continue on. I've used this before to keep a string alive long enough for a context where it may have been either allocated (and therefore need a place to hang its destructor) or came from some other string that lived longer than the function anyways.