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[73.152.9.216]) by smtp.gmail.com with ESMTPSA id w20sm5454010qkj.116.2021.08.27.17.20.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 27 Aug 2021 17:20:22 -0700 (PDT) Subject: Re: Error in 'man operator' To: "Alejandro Colomar (man-pages)" Cc: linux-man@vger.kernel.org, mtk.manpages@gmail.com References: <4cc4d818-58ad-529e-dd25-df3cb0fae66d@gmail.com> <71c78812-940e-8c15-c9ae-0dcde955232d@gmail.com> <40cbdcb1-1356-b749-ed53-61ed9dc2dd2e@gmail.com> <6666465a-ad5d-d8f7-92b1-35733f645961@gmail.com> From: David Sletten Message-ID: <2c0b0fb7-1f52-4e7f-86a7-65ec2bf2887d@gmail.com> Date: Fri, 27 Aug 2021 20:20:21 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <6666465a-ad5d-d8f7-92b1-35733f645961@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org Ha. Nice work. On 8/27/21 8:17 PM, Alejandro Colomar (man-pages) wrote: > Hi David, > > On 8/28/21 2:01 AM, Alejandro Colomar (man-pages) wrote: >> I mean: >> !(int)x >> (int)!x >> >> The precedence doesn't matter there, as they apply one after the >> other, right to left. >> >> So, I'll keep casts in row 2. > > Hmm, I just came up with some very stupid piece of code that can show > the different precedence between "unary operators" and "cast operators": > > sizeof(int)x; > > Which I hope no-one on earth would ever want to be valid C. > > If casts had the same precedence as unary operators, this would be: > First, cast x to int, then apply sizeof to the resulting int (since > sizeof can be used without parentheses on non-types). > > But since sizeof has greater precedence than the cast, it would be: > First, calculate sizeof(int), then... x?  Invalid expression! > > And luckily, the second thing happens, and the compiler yells: > > sizeof.c: In function ‘foo’: > sizeof.c:3:20: error: expected ‘;’ before ‘x’ >     3 |  return sizeof(int)x; >       |                    ^ >       |                    ; > > > So I think this deserves a new row. > > Thanks! > > Alex > >> >> Cheers, >> >> Alex >> > > -- Have all good days! David Sletten