[erlang-questions] Return value: optimization?

[Loïc Hoguin]

It's to inform Dialyzer that yes, we really do want to ignore the 
returned value. Should have no impact on execution otherwise.

On 02/01/2015 04:12 PM, Roberto Ostinelli wrote:
> Dear list,
> I was going through cowboy's code and I keep on seeing patterns such as
> this:
>
> _ = cowboy_req:reply(Status, Req),   [1]
>
> or this one:
>
> _ = case TRef of
> undefined -> ignore;
> TRef -> erlang:cancel_timer(TRef)
> end,  [2]
>
> All of these are done when we're there's no tail recursion. So now I'm
> curious: what is the purpose of explicitly assigning an anonymous
> variable to these expressions? Is this some kind of memory optimisation
> I'm just now aware of?
>
> Best,
> r.
>
>
> [1]
> https://github.com/ninenines/cowboy/blob/1.0.1/src/cowboy_protocol.erl#L504
> [2]
> https://github.com/ninenines/cowboy/blob/1.0.1/src/cowboy_handler.erl#L274
>
>
>
>
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-- 
Loïc Hoguin
http://ninenines.eu