Re: ignore_unused

From: Gavin Lambert (boost_at_[hidden])
Date: 2022-04-18 23:40:28

On 17/04/2022 03:59, Glen Fernandes wrote:
> Doesn't always work. For example: https://godbolt.org/z/3zn11ErKG

That's not really a common usage pattern, though, unless there are some 
conditional compilation constructs (#if or assert) involved; you just 
wouldn't assign it to a variable in the first place.

Typically `(void) x` is only used for parameters, and `(void) f()` for 
method calls (although most compilers will not complain by default about 
discarded return values, though that can usually be enabled).

> For those rare users that can afford to target C++17 or higher, they
> have [[maybe_unused]]

That attribute name irks me.  [[may_be_unused]] would have been better, 
or just [[unused]] (to save typing).

"May be unused" denotes permission, while "maybe unused" denotes 
uncertainty.  And you shouldn't be uncertain about your code.

Also compare with [[nodiscard]] (and as always, C++ having the opposite 
default of the correct one, due to backwards compatibility).