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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48700658441sm72115895e9.4.2026.03.20.07.45.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Mar 2026 07:45:01 -0700 (PDT) Date: Fri, 20 Mar 2026 14:44:59 +0000 From: David Laight To: Rodrigo Alencar <455.rodrigo.alencar@gmail.com> Cc: Andy Shevchenko , rodrigo.alencar@analog.com, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-doc@vger.kernel.org, Jonathan Cameron , David Lechner , Andy Shevchenko , Lars-Peter Clausen , Michael Hennerich , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jonathan Corbet , Andrew Morton Subject: Re: [PATCH v8 02/10] lib: kstrtox: add kstrntoull() helper Message-ID: <20260320144459.705c8e60@pumpkin> In-Reply-To: References: <20260303-adf41513-iio-driver-v8-0-8dd2417cc465@analog.com> <20260303-adf41513-iio-driver-v8-2-8dd2417cc465@analog.com> <4mtdzxfj656sjr66npabfvrr7yd7q26l2unhsihjtniz4ossfj@g3qnzonoary6> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 20 Mar 2026 12:41:57 +0000 Rodrigo Alencar <455.rodrigo.alencar@gmail.com> wrote: ... > > Some (stupid) thoughts loudly. IIUC even if we implement '%g' in scanf(), it > > wont help you as you want to have more precise values. Do I get it correct? > > If I am parsing 3.14159265359 with 6 decimal precision I want to stop at: > > frac = 141592 > int = 3 > > and ignore the rest. > If you add an 'upper limit' parameter and return a pointer to the digit that exceeds the limit (which would normally get processed as a syntax error) then you could have: int_part = strtoull(pi, &end, ~0ull, 10); if (end[0] == '.' && isdigit(end[1])) { frac = strtoull(end + 2, &end, 999999, 10); while (isdigit(*end)) end++; } Passing in the limit should help strtol() are strtoi() as well. David