From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34E8BC43460 for ; Fri, 16 Apr 2021 20:34:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 06E7C613CF for ; Fri, 16 Apr 2021 20:34:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343525AbhDPUfU (ORCPT ); Fri, 16 Apr 2021 16:35:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49102 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343509AbhDPUfU (ORCPT ); Fri, 16 Apr 2021 16:35:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618605294; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cnQ1WYK1Q/fzVZJP5dTDD7O6rnfjXe0Zb86HEbMOmAg=; b=Jyq6MvGwxcHCCJA8Yfaaf8pmGaF3SA6yRG+HtrQDhvLFG/SnS5QX3ZB3RULdZYs3MwIIQL N8feh2kU7ISxyzgLc79k+4e0cxnGx+jA1j4OlxqHCx2YyfN2EmZZejidsVdrn+PIdagKug kgVMBEhLyiyitZLxL6uP+MOrFXl6roI= Received: from mail-ot1-f69.google.com (mail-ot1-f69.google.com [209.85.210.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-360-1d4ixkwJN5-QOQN_zqmaRw-1; Fri, 16 Apr 2021 16:34:53 -0400 X-MC-Unique: 1d4ixkwJN5-QOQN_zqmaRw-1 Received: by mail-ot1-f69.google.com with SMTP id k24-20020a0568301bf8b02902844cbdb5feso5286952otb.5 for ; Fri, 16 Apr 2021 13:34:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=cnQ1WYK1Q/fzVZJP5dTDD7O6rnfjXe0Zb86HEbMOmAg=; b=mIliaXjGVpYVPWsDIS2PoXCw+tOLJSpx1IkLXqOQVA1vAS3QSn+BYgzdo2GqP6qbjV heGmKSq7yc9wI2OSZxaSlHnPEQZu843f6WYGNuUpaz4MmzOHy+cUX/XRFAcUvMJWM4/4 izkJ6GrIH+qgmcMJej5AytP/HtfUO4rdBKB1x6khvMoFAiG05/QaSS4tweqyoi/PIJWs ol095gwtXaXZV244yekJeDqmm6JStVCtKGyH/OOyMbedA1sgqrXbX9nHrD/AsjjEnzKP /ULU1YdlGa/v91FiYH/ZeZijQ9Wa3bzCd7WeQOiQNMTHWZRXkRrw2ocZV226jl3tv/nC gs+w== X-Gm-Message-State: AOAM532E84V821BrcxoKKQr3lHK6IiuIgC5hWNtU0zdzRkByrS7CegB9 qqL54ELQ+K1eYU7TWYpA40I1XIT+NhbluIwYM/TFZECYuZrstXUHGxxgOfX8rYfymjl87LAXSR9 y7bOaxH3VCaCuH1guwBRa X-Received: by 2002:a05:6808:c7:: with SMTP id t7mr1055087oic.43.1618605292401; Fri, 16 Apr 2021 13:34:52 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwDMeiBTSr4JPC5fMGzlWAn3gckHs2z8NaKVn5KrdX3KcjblRSMUGrgWzBCK6PA2rqcIxQZiA== X-Received: by 2002:a05:6808:c7:: with SMTP id t7mr1055071oic.43.1618605292143; Fri, 16 Apr 2021 13:34:52 -0700 (PDT) Received: from [192.168.0.173] (ip68-103-222-6.ks.ok.cox.net. [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> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@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.