[{"id":37523,"web_url":"https://patchwork.libcamera.org/comment/37523/","msgid":"<20260107203334.GH20168@pendragon.ideasonboard.com>","date":"2026-01-07T20:33:34","subject":"Re: [RFC PATCH v1 4/5] treewide: Use character literal instead of\n\tstring in some cases","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"On Wed, Jan 07, 2026 at 08:36:06PM +0100, Barnabás Pőcze wrote:\n> Use character literals instead of single character long strings. The main\n> purpose of this change is to work around a GCC (libstdc++) bug that results\n> in `-Wrestrict` warnings at certain optimization levels in C++20.\n\nHas it been fixed in libstdc++ ? The bug report seems to indicate a\nworkaround has been merged in gcc 13.1. I'd list that in the commit\nmessage.\n\n> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105329\n> Signed-off-by: Barnabás Pőcze \n> ---\n> src/libcamera/base/log.cpp | 12 ++++++------\n> src/libcamera/media_pipeline.cpp | 6 +++---\n> src/libcamera/pipeline/simple/simple.cpp | 6 +++---\n> 3 files changed, 12 insertions(+), 12 deletions(-)\n> \n> diff --git a/src/libcamera/base/log.cpp b/src/libcamera/base/log.cpp\n> index b28217750..946bdebf0 100644\n> --- a/src/libcamera/base/log.cpp\n> +++ b/src/libcamera/base/log.cpp\n> @@ -236,8 +236,8 @@ void LogOutput::write(const LogMessage &msg)\n> \n> \tswitch (target_) {\n> \tcase LoggingTargetSyslog:\n> -\t\tstr = std::string(log_severity_name(severity)) + \" \"\n> -\t\t + msg.category().name() + \" \" + msg.fileInfo() + \" \";\n> +\t\tstr = std::string(log_severity_name(severity)) + ' '\n> +\t\t + msg.category().name() + ' ' + msg.fileInfo() + ' ';\n\nWe'll have to remember to use characters instead of strings, which isn't\nvery nice, but I can't think of a better workaround. CI should catch the\nissues.\n\nReviewed-by: Laurent Pinchart \n\n> \t\tif (!msg.prefix().empty())\n> \t\t\tstr += msg.prefix() + \": \";\n> \t\tstr += msg.msg();\n> @@ -245,11 +245,11 @@ void LogOutput::write(const LogMessage &msg)\n> \t\tbreak;\n> \tcase LoggingTargetStream:\n> \tcase LoggingTargetFile:\n> -\t\tstr = \"[\" + utils::time_point_to_string(msg.timestamp()) + \"] [\"\n> +\t\tstr = '[' + utils::time_point_to_string(msg.timestamp()) + \"] [\"\n> \t\t + std::to_string(Thread::currentId()) + \"] \"\n> -\t\t + severityColor + log_severity_name(severity) + \" \"\n> -\t\t + categoryColor + msg.category().name() + \" \"\n> -\t\t + fileColor + msg.fileInfo() + \" \";\n> +\t\t + severityColor + log_severity_name(severity) + ' '\n> +\t\t + categoryColor + msg.category().name() + ' '\n> +\t\t + fileColor + msg.fileInfo() + ' ';\n> \t\tif (!msg.prefix().empty())\n> \t\t\tstr += prefixColor + msg.prefix() + \": \";\n> \t\tstr += resetColor + msg.msg();\n> diff --git a/src/libcamera/media_pipeline.cpp b/src/libcamera/media_pipeline.cpp\n> index 3c5517314..26c60c36b 100644\n> --- a/src/libcamera/media_pipeline.cpp\n> +++ b/src/libcamera/media_pipeline.cpp\n> @@ -243,11 +243,11 @@ int MediaPipeline::init(MediaEntity *source, std::string_view sink)\n> \t\t\t [](const Entity &e) {\n> \t\t\t\t std::string s = \"[\";\n> \t\t\t\t if (e.sink)\n> -\t\t\t\t\t s += std::to_string(e.sink->index()) + \"|\";\n> +\t\t\t\t\t s += std::to_string(e.sink->index()) + '|';\n> \t\t\t\t s += e.entity->name();\n> \t\t\t\t if (e.source)\n> -\t\t\t\t\t s += \"|\" + std::to_string(e.source->index());\n> -\t\t\t\t s += \"]\";\n> +\t\t\t\t\t s += '|' + std::to_string(e.source->index());\n> +\t\t\t\t s += ']';\n> \t\t\t\t return s;\n> \t\t\t });\n> \n> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp\n> index b30b0a122..d37b76a48 100644\n> --- a/src/libcamera/pipeline/simple/simple.cpp\n> +++ b/src/libcamera/pipeline/simple/simple.cpp\n> @@ -578,11 +578,11 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,\n> \t\t\t [](const Entity &e) {\n> \t\t\t\t std::string s = \"[\";\n> \t\t\t\t if (e.sink)\n> -\t\t\t\t\t s += std::to_string(e.sink->index()) + \"|\";\n> +\t\t\t\t\t s += std::to_string(e.sink->index()) + '|';\n> \t\t\t\t s += e.entity->name();\n> \t\t\t\t if (e.source)\n> -\t\t\t\t\t s += \"|\" + std::to_string(e.source->index());\n> -\t\t\t\t s += \"]\";\n> +\t\t\t\t\t s += '|' + std::to_string(e.source->index());\n> +\t\t\t\t s += ']';\n> \t\t\t\t return s;\n> \t\t\t });\n> }","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 46205BE08B\n\tfor ;\n\tWed, 7 Jan 2026 20:33:56 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7FA2061FA0;\n\tWed, 7 Jan 2026 21:33:55 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 43FD061F84\n\tfor ;\n\tWed, 7 Jan 2026 21:33:53 +0100 (CET)","from pendragon.ideasonboard.com (81-175-209-152.bb.dnainternet.fi\n\t[81.175.209.152])\n\tby perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 2DEFA593;\n\tWed, 7 Jan 2026 21:33:31 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"WJfJHJJK\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1767818011;\n\tbh=HoAk68BSr5LOFEicO9e9wTU0do4kUR0LaQ2crIiDTa4=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=WJfJHJJKqXs4WeHHlpTT1nmanUkib6Gm/4RRUBlBwdZba2S8y20i1o+5iZ4y22jr0\n\tUCERR6FY5OPjseMeEJvoL2jYQ1taBf/HtajMUJzZ98ELAkXBvVgW1DJYvXlWnkVejs\n\tBO8eUEd/DsXp6D42Qej3zt9JKGTsw/29lDi/rQds=","Date":"Wed, 7 Jan 2026 22:33:34 +0200","From":"Laurent Pinchart ","To":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","Cc":"libcamera-devel@lists.libcamera.org,\n\tNaushir Patuck ","Subject":"Re: [RFC PATCH v1 4/5] treewide: Use character literal instead of\n\tstring in some cases","Message-ID":"<20260107203334.GH20168@pendragon.ideasonboard.com>","References":"<20260107193607.2168539-1-barnabas.pocze@ideasonboard.com>\n\t<20260107193607.2168539-5-barnabas.pocze@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","Content-Transfer-Encoding":"8bit","In-Reply-To":"<20260107193607.2168539-5-barnabas.pocze@ideasonboard.com>","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":37562,"web_url":"https://patchwork.libcamera.org/comment/37562/","msgid":"","date":"2026-01-12T09:53:45","subject":"Re: [RFC PATCH v1 4/5] treewide: Use character literal instead of\n\tstring in some cases","submitter":{"id":34,"url":"https://patchwork.libcamera.org/api/people/34/","name":"Naushir Patuck","email":"naush@raspberrypi.com"},"content":"Hi Barnabás,\n\nOn Wed, 7 Jan 2026 at 19:36, Barnabás Pőcze\n wrote:\n>\n> Use character literals instead of single character long strings. The main\n> purpose of this change is to work around a GCC (libstdc++) bug that results\n> in `-Wrestrict` warnings at certain optimization levels in C++20.\n>\n> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105329\n> Signed-off-by: Barnabás Pőcze \n\nReviewed-by: Naushir Patuck \n\n> ---\n> src/libcamera/base/log.cpp | 12 ++++++------\n> src/libcamera/media_pipeline.cpp | 6 +++---\n> src/libcamera/pipeline/simple/simple.cpp | 6 +++---\n> 3 files changed, 12 insertions(+), 12 deletions(-)\n>\n> diff --git a/src/libcamera/base/log.cpp b/src/libcamera/base/log.cpp\n> index b28217750..946bdebf0 100644\n> --- a/src/libcamera/base/log.cpp\n> +++ b/src/libcamera/base/log.cpp\n> @@ -236,8 +236,8 @@ void LogOutput::write(const LogMessage &msg)\n>\n> switch (target_) {\n> case LoggingTargetSyslog:\n> - str = std::string(log_severity_name(severity)) + \" \"\n> - + msg.category().name() + \" \" + msg.fileInfo() + \" \";\n> + str = std::string(log_severity_name(severity)) + ' '\n> + + msg.category().name() + ' ' + msg.fileInfo() + ' ';\n> if (!msg.prefix().empty())\n> str += msg.prefix() + \": \";\n> str += msg.msg();\n> @@ -245,11 +245,11 @@ void LogOutput::write(const LogMessage &msg)\n> break;\n> case LoggingTargetStream:\n> case LoggingTargetFile:\n> - str = \"[\" + utils::time_point_to_string(msg.timestamp()) + \"] [\"\n> + str = '[' + utils::time_point_to_string(msg.timestamp()) + \"] [\"\n> + std::to_string(Thread::currentId()) + \"] \"\n> - + severityColor + log_severity_name(severity) + \" \"\n> - + categoryColor + msg.category().name() + \" \"\n> - + fileColor + msg.fileInfo() + \" \";\n> + + severityColor + log_severity_name(severity) + ' '\n> + + categoryColor + msg.category().name() + ' '\n> + + fileColor + msg.fileInfo() + ' ';\n> if (!msg.prefix().empty())\n> str += prefixColor + msg.prefix() + \": \";\n> str += resetColor + msg.msg();\n> diff --git a/src/libcamera/media_pipeline.cpp b/src/libcamera/media_pipeline.cpp\n> index 3c5517314..26c60c36b 100644\n> --- a/src/libcamera/media_pipeline.cpp\n> +++ b/src/libcamera/media_pipeline.cpp\n> @@ -243,11 +243,11 @@ int MediaPipeline::init(MediaEntity *source, std::string_view sink)\n> [](const Entity &e) {\n> std::string s = \"[\";\n> if (e.sink)\n> - s += std::to_string(e.sink->index()) + \"|\";\n> + s += std::to_string(e.sink->index()) + '|';\n> s += e.entity->name();\n> if (e.source)\n> - s += \"|\" + std::to_string(e.source->index());\n> - s += \"]\";\n> + s += '|' + std::to_string(e.source->index());\n> + s += ']';\n> return s;\n> });\n>\n> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp\n> index b30b0a122..d37b76a48 100644\n> --- a/src/libcamera/pipeline/simple/simple.cpp\n> +++ b/src/libcamera/pipeline/simple/simple.cpp\n> @@ -578,11 +578,11 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,\n> [](const Entity &e) {\n> std::string s = \"[\";\n> if (e.sink)\n> - s += std::to_string(e.sink->index()) + \"|\";\n> + s += std::to_string(e.sink->index()) + '|';\n> s += e.entity->name();\n> if (e.source)\n> - s += \"|\" + std::to_string(e.source->index());\n> - s += \"]\";\n> + s += '|' + std::to_string(e.source->index());\n> + s += ']';\n> return s;\n> });\n> }\n> --\n> 2.52.0\n>","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 A124BBDCBF\n\tfor ;\n\tMon, 12 Jan 2026 09:54:26 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 8B0C961FBB;\n\tMon, 12 Jan 2026 10:54:25 +0100 (CET)","from mail-ua1-x92a.google.com (mail-ua1-x92a.google.com\n\t[IPv6:2607:f8b0:4864:20::92a])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 8392561F9F\n\tfor ;\n\tMon, 12 Jan 2026 10:54:23 +0100 (CET)","by mail-ua1-x92a.google.com with SMTP id\n\ta1e0cc1a2514c-941262863abso145391241.1\n\tfor ;\n\tMon, 12 Jan 2026 01:54:23 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (2048-bit key;\n\tunprotected) header.d=raspberrypi.com header.i=@raspberrypi.com\n\theader.b=\"VDi9Jfle\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=raspberrypi.com; s=google; t=1768211662; x=1768816462;\n\tdarn=lists.libcamera.org; \n\th=content-transfer-encoding:cc:to:subject:message-id:date:from\n\t:in-reply-to:references:mime-version:from:to:cc:subject:date\n\t:message-id:reply-to;\n\tbh=ximvU0mG5PBcqvsOZNNfubCL5jIUGMGrUnFLNvlniKc=;\n\tb=VDi9JfleDHKIq0gug4+K48dj7bkh3eSK0fCYwDuEW8qXETLMm30kLgOTpPTHEKrE7Z\n\tK/kJ3lYRXFvrGPakBYVnDcZyXXKEKn4ZVcm4M0xfaCo/ov2jNV5JCzgyDuPC5X9VCfI0\n\tmf0XSfH12aYUt6alKbJkS8PinNjkDsp1NI2JorpJoCPQiaw/TXSIwgOeMT3CQynmaRt+\n\tgX9rW9lOJ+oGmbiV6/fdwyYxMG9/oG5zBg3sDmo1aWjznpTWgI+ZCaOGxdZnk7NHjZHb\n\tREMaZrcfBOl0fSloBuMlZ8GjEv8Br/gVKzOtUrjAX9UDfTjxESFxSR2zfxFlLvcjr1LJ\n\tUQhg==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20230601; t=1768211662; x=1768816462;\n\th=content-transfer-encoding:cc:to:subject:message-id:date:from\n\t:in-reply-to:references:mime-version:x-gm-gg:x-gm-message-state:from\n\t:to:cc:subject:date:message-id:reply-to;\n\tbh=ximvU0mG5PBcqvsOZNNfubCL5jIUGMGrUnFLNvlniKc=;\n\tb=vrpOhHGMrHJr2M96CJ/DJvq7OgYpVryDgrmbBDlMnmKMyQfhxv2jU17p0ckNfE6Bp5\n\tbGTkpQim2MQEum/WM6GELyMd3P2vv0R0sTFO9Ohk+y03aQJDuklduSoUQrMwxqxuudmX\n\tzCVgV4vuoAi4MN0nV8gC1Pkbu/WqXT7CiymRTjGkZymUeHF+M7DjJevgl6iSEfLURLtC\n\tdqlPJbaOFihj6RvP1Vu2PINkFDhtD8GDVYvByzkWLaDeJyPMzMx2Gj7AIFIxQuEzRZmP\n\toaeE9MATd/ZiymtphtintJVtjif72CvoCZ1t8C/kwPCtkrfz2dXvfbL/Zx8sLqPW0L0I\n\t6avQ==","X-Gm-Message-State":"AOJu0YydP2Ze6uShmH9TG9gNKZi4dBuY+nHJB2wh8AM2GDrOZmV3SP7o\n\trEJ1ZRfa5R52lSEnlhnqQ8h1uC4GF0mDt3MoxiJ5hpT86BPXVuYHQVpGhJ7QGhcptG7xpIZTj3W\n\tmW/MeqIA2XbdPmrdtlh5cV92d/nAQIt0WWprc9D3t0w==","X-Gm-Gg":"AY/fxX79N7/UKBEvHRrrNKHQrP8MDSwKHO3pRt3Z2r+0kMlsYnEMPtUXJQjQSgf6zyV\n\tHbldVPr+Cr21iGd8lTlDSkffHbw08CfXM3l7RxLslFN6/+2+iwIgVPe23MIj4fzxDTZb7GdLCv9\n\tIvyMOgMhRSEyxV6ze56UokNPiSVqJp63lBRIbuB5uFoL8yrpEJSaRtM4OiOVyZiA09AD6lWT49o\n\tv0ha0FQ4RwHjhx29axZYT2JVSUQmWIwPD6vc5m23je9VPm+KIldp4Z2s7s/P1ds+k5LFj1XqWQE\n\thxBisJDKkMo42QHd4oa8LdAF6os=","X-Google-Smtp-Source":"AGHT+IEFRmJ7GrMR7nw+GoPTP5mDPNnnoaR8Wiq9Nmc+NTRPD4Kan1M0JoBGlgKBBnXWMw0FnJx4blXbcLzFdBqTf38=","X-Received":"by 2002:a67:e715:0:b0:5df:b81d:b73e with SMTP id\n\tada2fe7eead31-5ecb698f47emr4313619137.8.1768211662177;\n\tMon, 12 Jan 2026 01:54:22 -0800 (PST)","MIME-Version":"1.0","References":"<20260107193607.2168539-1-barnabas.pocze@ideasonboard.com>\n\t<20260107193607.2168539-5-barnabas.pocze@ideasonboard.com>","In-Reply-To":"<20260107193607.2168539-5-barnabas.pocze@ideasonboard.com>","From":"Naushir Patuck ","Date":"Mon, 12 Jan 2026 09:53:45 +0000","X-Gm-Features":"AZwV_QhoSkV4FzbeRyboGGtARa6_sBLfq1HA1k4cCkWJ8u89tyd1EswR9kzW0lc","Message-ID":"","Subject":"Re: [RFC PATCH v1 4/5] treewide: Use character literal instead of\n\tstring in some cases","To":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","Cc":"libcamera-devel@lists.libcamera.org","Content-Type":"text/plain; charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]