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[68.103.222.6]) by smtp.gmail.com with ESMTPSA id c21sm1431581ooa.48.2021.04.16.13.34.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 16 Apr 2021 13:34:51 -0700 (PDT) Subject: Re: [PATCH 04/13] Kbuild: Rust support To: Willy Tarreau , Miguel Ojeda Cc: Al Viro , Linus Torvalds , Peter Zijlstra , Miguel Ojeda , Greg Kroah-Hartman , rust-for-linux@vger.kernel.org, Linux Kbuild mailing list , "open list:DOCUMENTATION" , Linux Kernel Mailing List , Alex Gaynor , Geoffrey Thomas , Finn Behrens , Adam Bratschi-Kaye , Wedson Almeida Filho , Michael Ellerman References: <20210414184604.23473-1-ojeda@kernel.org> <20210414184604.23473-5-ojeda@kernel.org> <20210416202215.GA11236@1wt.eu> From: Connor Kuehl Message-ID: Date: Fri, 16 Apr 2021 15:34:50 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210416202215.GA11236@1wt.eu> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ckuehl@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: rust-for-linux@vger.kernel.org On 4/16/21 3:22 PM, Willy Tarreau wrote: > So it simply does the equivalent of: > > #define EINVAL -1234 > > struct result { > int status; > int error; > }; Result and Option types are more like a union with a tag that describes which variant it is. struct foo_result { /* if ok, then access foo_or_err.successful_foo * else, access foo_or_err.error */ bool ok; union { struct foo successful_foo; int error; } foo_or_err; }; > [..] > > So it simply returns a pair of values instead of a single one, which It will only return 1 value.