[{"id":38874,"web_url":"https://patchwork.libcamera.org/comment/38874/","msgid":"<72fcad7d-c6dd-4ed8-94c1-3b39e4b8bc9d@ideasonboard.com>","date":"2026-05-12T14:30:50","subject":"Re: [PATCH] apps: common: options: Use character literal instead of\n\tstring","submitter":{"id":216,"url":"https://patchwork.libcamera.org/api/people/216/","name":"Barnabás Pőcze","email":"barnabas.pocze@ideasonboard.com"},"content":"2026. 05. 12. 16:18 keltezéssel, Laurent Pinchart írta:\n> gcc 12 generates a `-Wrestrict` warning at -O3 optimization levels in\n> C++20:\n> \n> g++-12 -Isrc/apps/common/libapps.a.p -Isrc/apps/common -I../src/apps/common -Iinclude -I../include -Iinclude/libcamera -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Werror -std=c++20 -O3 -Wnon-virtual-dtor -Wno-redundant-move -Wmissing-declarations -Wshadow -include /builds/pinchartl/libcamera/build/config.h -fPIC -DHAVE_TIFF -MD -MQ src/apps/common/libapps.a.p/options.cpp.o -MF src/apps/common/libapps.a.p/options.cpp.o.d -o src/apps/common/libapps.a.p/options.cpp.o -c ../src/apps/common/options.cpp\n> In file included from /usr/include/c++/12/string:40,\n> from /usr/include/c++/12/bits/locale_classes.h:40,\n> from /usr/include/c++/12/bits/ios_base.h:41,\n> from /usr/include/c++/12/iomanip:40,\n> from ../src/apps/common/options.cpp:10:\n> In static member function ‘static constexpr std::char_traits::char_type* std::char_traits::copy(char_type*, const char_type*, std::size_t)’,\n> inlined from ‘static constexpr void std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_S_copy(_CharT*, const _CharT*, size_type) [with _CharT = char; _Traits = std::char_traits; _Alloc = std::allocator]’ at /usr/include/c++/12/bits/basic_string.h:423:21,\n> inlined from ‘constexpr std::__cxx11::basic_string<_CharT, _Traits, _Allocator>& std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_replace(size_type, size_type, const _CharT*, size_type) [with _CharT = char; _Traits = std::char_traits; _Alloc = std::allocator]’ at /usr/include/c++/12/bits/basic_string.tcc:532:22,\n> inlined from ‘constexpr std::__cxx11::basic_string<_CharT, _Traits, _Alloc>& std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::replace(size_type, size_type, const _CharT*, size_type) [with _CharT = char; _Traits = std::char_traits; _Alloc = std::allocator]’ at /usr/include/c++/12/bits/basic_string.h:2171:19,\n> inlined from ‘constexpr std::__cxx11::basic_string<_CharT, _Traits, _Alloc>& std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::insert(size_type, const _CharT*) [with _CharT = char; _Traits = std::char_traits; _Alloc = std::allocator]’ at /usr/include/c++/12/bits/basic_string.h:1928:22,\n> inlined from ‘constexpr std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&) [with _CharT = char; _Traits = char_traits; _Alloc = allocator]’ at /usr/include/c++/12/bits/basic_string.h:3541:36,\n> inlined from ‘std::string Option::optionName() const’ at ../src/apps/common/options.cpp:149:34:\n> /usr/include/c++/12/bits/char_traits.h:431:56: error: ‘void* __builtin_memcpy(void*, const void*, long unsigned int)’ accessing 9223372036854775810 or more bytes at offsets [18, 9223372036854775807] and 17 may overlap up to 9223372036854775813 bytes at offset -3 [-Werror=restrict]\n> 431 | return static_cast(__builtin_memcpy(__s1, __s2, __n));\n> | ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~\n> \n> Work around the issue by using a character literal instead of a string\n> literal for single character strings.\n> \n> Signed-off-by: Laurent Pinchart \n> ---\n\nReviewed-by: Barnabás Pőcze \n\n\n> src/apps/common/options.cpp | 2 +-\n> 1 file changed, 1 insertion(+), 1 deletion(-)\n> \n> diff --git a/src/apps/common/options.cpp b/src/apps/common/options.cpp\n> index b95f95afadf3..be0c161165ea 100644\n> --- a/src/apps/common/options.cpp\n> +++ b/src/apps/common/options.cpp\n> @@ -146,7 +146,7 @@ std::string Option::optionName() const\n> \tif (name)\n> \t\treturn \"--\" + std::string(name);\n> \telse\n> -\t\treturn \"-\" + std::string(1, opt);\n> +\t\treturn '-' + std::string(1, opt);\n> }\n> \n> /* -----------------------------------------------------------------------------\n> \n> base-commit: b0dbd5100b1b1665dd2bc839d06263d55a89a6bd","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 3371DBDB1C\n\tfor ;\n\tTue, 12 May 2026 14:30:56 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7F1EE62FEA;\n\tTue, 12 May 2026 16:30:55 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id D035A6271A\n\tfor ;\n\tTue, 12 May 2026 16:30:53 +0200 (CEST)","from [192.168.33.39] (185.182.215.166.nat.pool.zt.hu\n\t[185.182.215.166])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id E8B2956D;\n\tTue, 12 May 2026 16:30:45 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; 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