[{"id":22925,"web_url":"https://patchwork.libcamera.org/comment/22925/","msgid":"","date":"2022-05-10T09:10:21","subject":"Re: [libcamera-devel] [PATCH] cam: convert to libfmt","submitter":{"id":109,"url":"https://patchwork.libcamera.org/api/people/109/","name":"Tomi Valkeinen","email":"tomi.valkeinen@ideasonboard.com"},"content":"On 10/05/2022 10:16, Tomi Valkeinen wrote:\n> This is just a conversation starter, not for merging. I really like\n> libfmt, and I really hate the C++ stream-based string formatting. libfmt\n> is the first library I add to any new C++ project I make.\n> \n> You can find more information about libfmt from:\n> \n> https://github.com/fmtlib/fmt\n> https://fmt.dev/latest/index.html\n> \n> This patch is just a crude conversion with ugly macros to showcase what\n> the formatting code might look like.\n\nAs for the PR and EPR macros, those was just something to get forward \nwith. I think fmt::print(\"\") is fine, but fmt::print(stderr, \"\") is a \nbit long.\n\nCompared to cout, \"fmt::print(\" is actually shorter than \"std::cout << \n\", and without all those << and std::endl the lines are shorter.\n\nNot so with cerr and fmt::print(stderr, (although in many cases the \ntotal length would still be shorter) but I think it makes sense to have \na macro/inline func for error prints, if only to make it more obvious \nthat it's an error print.\n\nAnd, of course, libfmt could also be used for logging:\n\nLOG(Camera, Error) << \"Camera in \" << camera_state_names[currentState]\n\t\t << \" state trying \" << from << \"() requiring state \"\n\t\t << camera_state_names[state];\n\nto\n\nLOG(Camera, Error, \"Camera in {} state trying {}() requiring state {}\",\n camera_state_names[currentState], from, camera_state_names[state]);\n\n Tomi","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 E314BC0F2A\n\tfor ;\n\tTue, 10 May 2022 09:10:26 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 5058E65641;\n\tTue, 10 May 2022 11:10:26 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id E624E6563E\n\tfor ;\n\tTue, 10 May 2022 11:10:24 +0200 (CEST)","from [192.168.1.111] (91-156-85-209.elisa-laajakaista.fi\n\t[91.156.85.209])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 4F15D55A;\n\tTue, 10 May 2022 11:10:24 +0200 (CEST)"],"DKIM-Signature":["v=1; a=rsa-sha256; c=relaxed/simple; d=libcamera.org;\n\ts=mail; t=1652173826;\n\tbh=FZODP/lLVo0mTVlO1UiwTrTkwxj8UNThp4AZoJZh+p8=;\n\th=Date:To:References:In-Reply-To:Subject:List-Id:List-Unsubscribe:\n\tList-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:\n\tFrom;\n\tb=J0E/Exp8CNvYovRI74FSwqnU4XeDzOGg9yFWqT76wEyRS8m5AeouT/4gLbW+H1Wc5\n\t7DrGmXa9AjPsBDA1kGnmNt3xFdIUruEtv4Bhg+A05a7lg6tUowLR+So7ChUftzCBDS\n\twoRhqXM7rx5dp5zV764UGyJnsgfaq+kon7xROx0Uu4AQTnJJFgBTOUrdE+whSed/Hb\n\tb9reBZHxsP8qmKG+ANRHSGcLwgLgYD3hFLZcHptUOXQtc78Q7GUbqKp6+uAaSKTnWm\n\te4sSFnlf1UIqfosa91jpVJJDsTdtsLxa+ocMs6+mXg4yFOTmM8EdVAcYyX11u0pmZs\n\t+Va8ix32AExCg==","v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1652173824;\n\tbh=FZODP/lLVo0mTVlO1UiwTrTkwxj8UNThp4AZoJZh+p8=;\n\th=Date:Subject:To:References:From:In-Reply-To:From;\n\tb=RyIr1WDtRu1UY66TkYXBnD+P1cMNWFTn+W5aNtGKEcuKfmOP+XWNVU2HZeNANrp8k\n\tqGj0gS/zAAyWKnPVMEWOyVmJ6f5BtdMzqaAIMN3bx73WqpDGZH7KfE2JceQj0QDsAa\n\tFBrJpY3JIBtgccQyIHVpcvvfWOJTv40+wO5eyVO0="],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key; \n\tunprotected) header.d=ideasonboard.com\n\theader.i=@ideasonboard.com\n\theader.b=\"RyIr1WDt\"; dkim-atps=neutral","Message-ID":"","Date":"Tue, 10 May 2022 12:10:21 +0300","MIME-Version":"1.0","User-Agent":"Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101\n\tThunderbird/91.8.0","Content-Language":"en-US","To":"libcamera-devel@lists.libcamera.org,\n\tKieran Bingham ,\n\tLaurent Pinchart ","References":"<20220510071617.42227-1-tomi.valkeinen@ideasonboard.com>","In-Reply-To":"<20220510071617.42227-1-tomi.valkeinen@ideasonboard.com>","Content-Type":"text/plain; charset=UTF-8; format=flowed","Content-Transfer-Encoding":"7bit","Subject":"Re: [libcamera-devel] [PATCH] cam: convert to libfmt","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","From":"Tomi Valkeinen via libcamera-devel\n\t","Reply-To":"Tomi Valkeinen ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":22929,"web_url":"https://patchwork.libcamera.org/comment/22929/","msgid":"","date":"2022-05-10T09:49:14","subject":"Re: [libcamera-devel] [PATCH] cam: convert to libfmt","submitter":{"id":34,"url":"https://patchwork.libcamera.org/api/people/34/","name":"Naushir Patuck","email":"naush@raspberrypi.com"},"content":"Hi Tomi,\n\nOn Tue, 10 May 2022 at 08:16, Tomi Valkeinen via libcamera-devel <\nlibcamera-devel@lists.libcamera.org> wrote:\n\n> This is just a conversation starter, not for merging. I really like\n> libfmt, and I really hate the C++ stream-based string formatting. libfmt\n> is the first library I add to any new C++ project I make.\n>\n> You can find more information about libfmt from:\n>\n> https://github.com/fmtlib/fmt\n> https://fmt.dev/latest/index.html\n>\n> This patch is just a crude conversion with ugly macros to showcase what\n> the formatting code might look like.\n>\n> libfmt pages suggest that libfmt would be faster and smaller (exe size)\n> than iostreams, but for the size it didn't seem to be true in cam's case\n> as the tests below show. However, simple prints did reduce the exe size,\n> but the few more complex ones increased the size.\n>\n> Size tests with gcc 11.2.0-19ubuntu1\n>\n> - Without libfmt\n>\n> debug 3523400\n> debug lto 3269368\n> release 223056\n> release lto 172280\n>\n> - With libfmt\n>\n> debug 4424256\n> debug lto 4143840\n> release 303952\n> release lto 252640\n>\n> Above shows that cam's size clearly increases with libfmt. However, the\n> increase really comes only from one case, the use of fmt::memory_buffer\n> and std::back_inserter. Converting that code to use fmt::format() and\n> naive string append gives:\n>\n> release with string append 233680\n> release lto with string append 186936\n>\n> Also, if I add another use of fmt::memory_buffer and std::back_inserter\n> to another file, I see much less increase in the size:\n>\n> release lto with two uses of memory_buffer, back_inserter 256736\n>\n> Signed-off-by: Tomi Valkeinen \n>\n\nFor what it's worth, I absolutely loathe formatting in std iostream, and\nlibfmt is a wonderful alternative.\nIt also is close enough to the C++20 std::format implementation that\neventual porting would be low effort. So I am all for this change :)\n\nRegards,\nNaush\n\n\n\n> ---\n> src/cam/camera_session.cpp | 105 ++++++++++++++++---------------------\n> src/cam/drm.cpp | 68 ++++++++----------------\n> src/cam/event_loop.cpp | 9 ++--\n> src/cam/file_sink.cpp | 31 +++++------\n> src/cam/image.cpp | 15 +++---\n> src/cam/kms_sink.cpp | 38 ++++++--------\n> src/cam/main.cpp | 28 +++++-----\n> src/cam/meson.build | 5 +-\n> src/cam/options.cpp | 66 ++++++++++-------------\n> src/cam/stream_options.cpp | 18 +++----\n> 10 files changed, 165 insertions(+), 218 deletions(-)\n>\n> diff --git a/src/cam/camera_session.cpp b/src/cam/camera_session.cpp\n> index efffafbf..7843c3fd 100644\n> --- a/src/cam/camera_session.cpp\n> +++ b/src/cam/camera_session.cpp\n> @@ -5,10 +5,9 @@\n> * camera_session.cpp - Camera capture session\n> */\n>\n> -#include \n> -#include \n> #include \n> -#include \n> +#include \n> +#include \n>\n> #include \n> #include \n> @@ -22,6 +21,9 @@\n> #include \"main.h\"\n> #include \"stream_options.h\"\n>\n> +#define PR(...) fmt::print(__VA_ARGS__)\n> +#define EPR(...) fmt::print(stderr, __VA_ARGS__)\n> +\n> using namespace libcamera;\n>\n> CameraSession::CameraSession(CameraManager *cm,\n> @@ -40,13 +42,12 @@ CameraSession::CameraSession(CameraManager *cm,\n> camera_ = cm->get(cameraId);\n>\n> if (!camera_) {\n> - std::cerr << \"Camera \" << cameraId << \" not found\" <<\n> std::endl;\n> + EPR(\"Camera {} not found\\n\", cameraId);\n> return;\n> }\n>\n> if (camera_->acquire()) {\n> - std::cerr << \"Failed to acquire camera \" << cameraId\n> - << std::endl;\n> + EPR(\"Failed to acquire camera {}\", cameraId);\n> return;\n> }\n>\n> @@ -55,15 +56,14 @@ CameraSession::CameraSession(CameraManager *cm,\n> std::unique_ptr config =\n> camera_->generateConfiguration(roles);\n> if (!config || config->size() != roles.size()) {\n> - std::cerr << \"Failed to get default stream configuration\"\n> - << std::endl;\n> + EPR(\"Failed to get default stream configuration\\n\");\n> return;\n> }\n>\n> /* Apply configuration if explicitly requested. */\n> if (StreamKeyValueParser::updateConfiguration(config.get(),\n>\n> options_[OptStream])) {\n> - std::cerr << \"Failed to update configuration\" << std::endl;\n> + EPR(\"Failed to update configuration\\n\");\n> return;\n> }\n>\n> @@ -72,20 +72,17 @@ CameraSession::CameraSession(CameraManager *cm,\n> #ifdef HAVE_KMS\n> if (options_.isSet(OptDisplay)) {\n> if (options_.isSet(OptFile)) {\n> - std::cerr << \"--display and --file options are\n> mutually exclusive\"\n> - << std::endl;\n> + EPR(\"--display and --file options are mutually\n> exclusive\\n\");\n> return;\n> }\n>\n> if (roles.size() != 1) {\n> - std::cerr << \"Display doesn't support multiple\n> streams\"\n> - << std::endl;\n> + EPR(\"Display doesn't support multiple streams\\n\");\n> return;\n> }\n>\n> if (roles[0] != StreamRole::Viewfinder) {\n> - std::cerr << \"Display requires a viewfinder stream\"\n> - << std::endl;\n> + EPR(\"Display requires a viewfinder stream\\n\");\n> return;\n> }\n> }\n> @@ -97,15 +94,14 @@ CameraSession::CameraSession(CameraManager *cm,\n>\n> case CameraConfiguration::Adjusted:\n> if (strictFormats) {\n> - std::cout << \"Adjusting camera configuration\n> disallowed by --strict-formats argument\"\n> - << std::endl;\n> + PR(\"Adjusting camera configuration disallowed by\n> --strict-formats argument\\n\");\n> return;\n> }\n> - std::cout << \"Camera configuration adjusted\" << std::endl;\n> + PR(\"Camera configuration adjusted\\n\");\n> break;\n>\n> case CameraConfiguration::Invalid:\n> - std::cout << \"Camera configuration invalid\" << std::endl;\n> + PR(\"Camera configuration invalid\\n\");\n> return;\n> }\n>\n> @@ -121,8 +117,7 @@ CameraSession::~CameraSession()\n> void CameraSession::listControls() const\n> {\n> for (const auto &[id, info] : camera_->controls()) {\n> - std::cout << \"Control: \" << id->name() << \": \"\n> - << info.toString() << std::endl;\n> + PR(\"Control: {}: {}}n\", id->name(), info.toString());\n> }\n> }\n>\n> @@ -131,8 +126,7 @@ void CameraSession::listProperties() const\n> for (const auto &[key, value] : camera_->properties()) {\n> const ControlId *id = properties::properties.at(key);\n>\n> - std::cout << \"Property: \" << id->name() << \" = \"\n> - << value.toString() << std::endl;\n> + PR(\"Property: {} = {}\\n\", id->name(), value.toString());\n> }\n> }\n>\n> @@ -140,17 +134,15 @@ void CameraSession::infoConfiguration() const\n> {\n> unsigned int index = 0;\n> for (const StreamConfiguration &cfg : *config_) {\n> - std::cout << index << \": \" << cfg.toString() << std::endl;\n> + PR(\"{}: {}\\n\", index, cfg.toString());\n>\n> const StreamFormats &formats = cfg.formats();\n> for (PixelFormat pixelformat : formats.pixelformats()) {\n> - std::cout << \" * Pixelformat: \"\n> - << pixelformat << \" \"\n> - << formats.range(pixelformat).toString()\n> - << std::endl;\n> + PR(\" * Pixelformat: {} {}\\n\", pixelformat,\n> + formats.range(pixelformat).toString());\n>\n> for (const Size &size : formats.sizes(pixelformat))\n> - std::cout << \" - \" << size << std::endl;\n> + PR(\" - {}\\n\", size);\n> }\n>\n> index++;\n> @@ -168,7 +160,7 @@ int CameraSession::start()\n>\n> ret = camera_->configure(config_.get());\n> if (ret < 0) {\n> - std::cout << \"Failed to configure camera\" << std::endl;\n> + PR(\"Failed to configure camera\\n\");\n> return ret;\n> }\n>\n> @@ -197,8 +189,7 @@ int CameraSession::start()\n> if (sink_) {\n> ret = sink_->configure(*config_);\n> if (ret < 0) {\n> - std::cout << \"Failed to configure frame sink\"\n> - << std::endl;\n> + PR(\"Failed to configure frame sink\\n\");\n> return ret;\n> }\n>\n> @@ -214,12 +205,12 @@ void CameraSession::stop()\n> {\n> int ret = camera_->stop();\n> if (ret)\n> - std::cout << \"Failed to stop capture\" << std::endl;\n> + PR(\"Failed to stop capture\\n\");\n>\n> if (sink_) {\n> ret = sink_->stop();\n> if (ret)\n> - std::cout << \"Failed to stop frame sink\" <<\n> std::endl;\n> + PR(\"Failed to stop frame sink\\n\");\n> }\n>\n> sink_.reset();\n> @@ -238,7 +229,7 @@ int CameraSession::startCapture()\n> for (StreamConfiguration &cfg : *config_) {\n> ret = allocator_->allocate(cfg.stream());\n> if (ret < 0) {\n> - std::cerr << \"Can't allocate buffers\" << std::endl;\n> + EPR(\"Can't allocate buffers\\n\");\n> return -ENOMEM;\n> }\n>\n> @@ -254,7 +245,7 @@ int CameraSession::startCapture()\n> for (unsigned int i = 0; i < nbuffers; i++) {\n> std::unique_ptr request =\n> camera_->createRequest();\n> if (!request) {\n> - std::cerr << \"Can't create request\" << std::endl;\n> + EPR(\"Can't create request\\n\");\n> return -ENOMEM;\n> }\n>\n> @@ -266,8 +257,7 @@ int CameraSession::startCapture()\n>\n> ret = request->addBuffer(stream, buffer.get());\n> if (ret < 0) {\n> - std::cerr << \"Can't set buffer for request\"\n> - << std::endl;\n> + EPR(\"Can't set buffer for request\\n\");\n> return ret;\n> }\n>\n> @@ -281,14 +271,14 @@ int CameraSession::startCapture()\n> if (sink_) {\n> ret = sink_->start();\n> if (ret) {\n> - std::cout << \"Failed to start frame sink\" <<\n> std::endl;\n> + PR(\"Failed to start frame sink\\n\");\n> return ret;\n> }\n> }\n>\n> ret = camera_->start();\n> if (ret) {\n> - std::cout << \"Failed to start capture\" << std::endl;\n> + PR(\"Failed to start capture\\n\");\n> if (sink_)\n> sink_->stop();\n> return ret;\n> @@ -297,7 +287,7 @@ int CameraSession::startCapture()\n> for (std::unique_ptr &request : requests_) {\n> ret = queueRequest(request.get());\n> if (ret < 0) {\n> - std::cerr << \"Can't queue request\" << std::endl;\n> + EPR(\"Can't queue request\\n\");\n> camera_->stop();\n> if (sink_)\n> sink_->stop();\n> @@ -306,13 +296,11 @@ int CameraSession::startCapture()\n> }\n>\n> if (captureLimit_)\n> - std::cout << \"cam\" << cameraIndex_\n> - << \": Capture \" << captureLimit_ << \" frames\"\n> - << std::endl;\n> + PR(\"cam{}: Capture {} frames\\n\", cameraIndex_,\n> + captureLimit_);\n> else\n> - std::cout << \"cam\" << cameraIndex_\n> - << \": Capture until user interrupts by SIGINT\"\n> - << std::endl;\n> + PR(\"cam{}: Capture until user interrupts by SIGINT\\n\",\n> + cameraIndex_);\n>\n> return 0;\n> }\n> @@ -364,23 +352,23 @@ void CameraSession::processRequest(Request *request)\n>\n> bool requeue = true;\n>\n> - std::stringstream info;\n> - info << ts / 1000000000 << \".\"\n> - << std::setw(6) << std::setfill('0') << ts / 1000 % 1000000\n> - << \" (\" << std::fixed << std::setprecision(2) << fps << \"\n> fps)\";\n> + auto sbuf = fmt::memory_buffer();\n> + fmt::format_to(std::back_inserter(sbuf), \"{}.{:06} ({:.2f} fps)\",\n> + ts / 1000000000,\n> + ts / 1000 % 1000000,\n> + fps);\n>\n> for (const auto &[stream, buffer] : buffers) {\n> const FrameMetadata &metadata = buffer->metadata();\n>\n> - info << \" \" << streamNames_[stream]\n> - << \" seq: \" << std::setw(6) << std::setfill('0') <<\n> metadata.sequence\n> - << \" bytesused: \";\n> + fmt::format_to(std::back_inserter(sbuf), \" {} seq: {:06}\n> bytesused: \",\n> + streamNames_[stream], metadata.sequence);\n>\n> unsigned int nplane = 0;\n> for (const FrameMetadata::Plane &plane :\n> metadata.planes()) {\n> - info << plane.bytesused;\n> + fmt::format_to(std::back_inserter(sbuf), \"{}\",\n> plane.bytesused);\n> if (++nplane < metadata.planes().size())\n> - info << \"/\";\n> + fmt::format_to(std::back_inserter(sbuf),\n> \"/\");\n> }\n> }\n>\n> @@ -389,14 +377,13 @@ void CameraSession::processRequest(Request *request)\n> requeue = false;\n> }\n>\n> - std::cout << info.str() << std::endl;\n> + PR(\"{}\\n\", fmt::to_string(sbuf));\n>\n> if (printMetadata_) {\n> const ControlList &requestMetadata = request->metadata();\n> for (const auto &[key, value] : requestMetadata) {\n> const ControlId *id = controls::controls.at(key);\n> - std::cout << \"\\t\" << id->name() << \" = \"\n> - << value.toString() << std::endl;\n> + PR(\"\\t{} = {}\\n\", id->name(), value.toString());\n> }\n> }\n>\n> diff --git a/src/cam/drm.cpp b/src/cam/drm.cpp\n> index 46e34eb5..84919ab3 100644\n> --- a/src/cam/drm.cpp\n> +++ b/src/cam/drm.cpp\n> @@ -10,12 +10,12 @@\n> #include \n> #include \n> #include \n> -#include \n> #include \n> #include \n> #include \n> #include \n> #include \n> +#include \n>\n> #include \n> #include \n> @@ -25,6 +25,9 @@\n>\n> #include \"event_loop.h\"\n>\n> +#define PR(...) fmt::print(__VA_ARGS__)\n> +#define EPR(...) fmt::print(stderr, __VA_ARGS__)\n> +\n> namespace DRM {\n>\n> Object::Object(Device *dev, uint32_t id, Type type)\n> @@ -178,9 +181,7 @@ Connector::Connector(Device *dev, const\n> drmModeConnector *connector)\n> {\n> auto typeName = connectorTypeNames.find(connector->connector_type);\n> if (typeName == connectorTypeNames.end()) {\n> - std::cerr\n> - << \"Invalid connector type \"\n> - << connector->connector_type << std::endl;\n> + EPR(\"Invalid connector type {}}n\",\n> connector->connector_type);\n> typeName =\n> connectorTypeNames.find(DRM_MODE_CONNECTOR_Unknown);\n> }\n>\n> @@ -213,9 +214,7 @@ Connector::Connector(Device *dev, const\n> drmModeConnector *connector)\n> return e.id() ==\n> encoderId;\n> });\n> if (encoder == encoders.end()) {\n> - std::cerr\n> - << \"Encoder \" << encoderId << \" not found\"\n> - << std::endl;\n> + EPR(\"Encoder {} not found\\n\", encoderId);\n> continue;\n> }\n>\n> @@ -296,9 +295,7 @@ FrameBuffer::~FrameBuffer()\n>\n> if (ret == -1) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to close GEM object: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to close GEM object: {}\\n\",\n> strerror(-ret));\n> }\n> }\n>\n> @@ -408,9 +405,8 @@ int Device::init()\n> fd_ = open(name, O_RDWR | O_CLOEXEC);\n> if (fd_ < 0) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to open DRM/KMS device \" << name << \": \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to open DRM/KMS device {}: {}\\n\", name,\n> + strerror(-ret));\n> return ret;\n> }\n>\n> @@ -421,9 +417,7 @@ int Device::init()\n> ret = drmSetClientCap(fd_, DRM_CLIENT_CAP_ATOMIC, 1);\n> if (ret < 0) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to enable atomic capability: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to enable atomic capability: {}\\n\",\n> strerror(-ret));\n> return ret;\n> }\n>\n> @@ -448,9 +442,7 @@ int Device::getResources()\n> };\n> if (!resources) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to get DRM/KMS resources: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to get DRM/KMS resources: {}\\n\",\n> strerror(-ret));\n> return ret;\n> }\n>\n> @@ -458,9 +450,7 @@ int Device::getResources()\n> drmModeCrtc *crtc = drmModeGetCrtc(fd_,\n> resources->crtcs[i]);\n> if (!crtc) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to get CRTC: \" << strerror(-ret)\n> - << std::endl;\n> + EPR(\"Failed to get CRTC: {}\\n\", strerror(-ret));\n> return ret;\n> }\n>\n> @@ -476,9 +466,7 @@ int Device::getResources()\n> drmModeGetEncoder(fd_, resources->encoders[i]);\n> if (!encoder) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to get encoder: \" <<\n> strerror(-ret)\n> - << std::endl;\n> + EPR(\"Failed to get encoder: {}\\n\", strerror(-ret));\n> return ret;\n> }\n>\n> @@ -494,9 +482,7 @@ int Device::getResources()\n> drmModeGetConnector(fd_, resources->connectors[i]);\n> if (!connector) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to get connector: \" <<\n> strerror(-ret)\n> - << std::endl;\n> + EPR(\"Failed to get connector: {}\\n\",\n> strerror(-ret));\n> return ret;\n> }\n>\n> @@ -513,9 +499,7 @@ int Device::getResources()\n> };\n> if (!planes) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to get DRM/KMS planes: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to get DRM/KMS planes: {}\\n\", strerror(-ret));\n> return ret;\n> }\n>\n> @@ -524,9 +508,7 @@ int Device::getResources()\n> drmModeGetPlane(fd_, planes->planes[i]);\n> if (!plane) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to get plane: \" <<\n> strerror(-ret)\n> - << std::endl;\n> + EPR(\"Failed to get plane: {}\\n\", strerror(-ret));\n> return ret;\n> }\n>\n> @@ -556,9 +538,7 @@ int Device::getResources()\n> drmModePropertyRes *property = drmModeGetProperty(fd_, id);\n> if (!property) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to get property: \" <<\n> strerror(-ret)\n> - << std::endl;\n> + EPR(\"Failed to get property: {}\\n\",\n> strerror(-ret));\n> continue;\n> }\n>\n> @@ -573,9 +553,8 @@ int Device::getResources()\n> for (auto &object : objects_) {\n> ret = object.second->setup();\n> if (ret < 0) {\n> - std::cerr\n> - << \"Failed to setup object \" <<\n> object.second->id()\n> - << \": \" << strerror(-ret) << std::endl;\n> + EPR(\"Failed to setup object {}: {}\\n\",\n> + object.second->id(), strerror(-ret));\n> return ret;\n> }\n> }\n> @@ -616,9 +595,8 @@ std::unique_ptr Device::createFrameBuffer(\n> ret = drmPrimeFDToHandle(fd_, plane.fd.get(),\n> &handle);\n> if (ret < 0) {\n> ret = -errno;\n> - std::cerr\n> - << \"Unable to import framebuffer\n> dmabuf: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Unable to import framebuffer dmabuf:\n> {}\\n\",\n> + strerror(-ret));\n> return nullptr;\n> }\n>\n> @@ -636,9 +614,7 @@ std::unique_ptr Device::createFrameBuffer(\n> strides.data(), offsets, &fb->id_, 0);\n> if (ret < 0) {\n> ret = -errno;\n> - std::cerr\n> - << \"Failed to add framebuffer: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to add framebuffer: {}\\n\", strerror(-ret));\n> return nullptr;\n> }\n>\n> diff --git a/src/cam/event_loop.cpp b/src/cam/event_loop.cpp\n> index e25784c0..87aaf59a 100644\n> --- a/src/cam/event_loop.cpp\n> +++ b/src/cam/event_loop.cpp\n> @@ -10,7 +10,10 @@\n> #include \n> #include \n> #include \n> -#include \n> +#include \n> +\n> +#define PR(...) fmt::print(__VA_ARGS__)\n> +#define EPR(...) fmt::print(stderr, __VA_ARGS__)\n>\n> EventLoop *EventLoop::instance_ = nullptr;\n>\n> @@ -71,13 +74,13 @@ void EventLoop::addEvent(int fd, EventType type,\n> event->event_ = event_new(base_, fd, events,\n> &EventLoop::Event::dispatch,\n> event.get());\n> if (!event->event_) {\n> - std::cerr << \"Failed to create event for fd \" << fd <<\n> std::endl;\n> + EPR(\"Failed to create event for fd {}\\n\", fd);\n> return;\n> }\n>\n> int ret = event_add(event->event_, nullptr);\n> if (ret < 0) {\n> - std::cerr << \"Failed to add event for fd \" << fd <<\n> std::endl;\n> + EPR(\"Failed to add event for fd {}\\n\", fd);\n> return;\n> }\n>\n> diff --git a/src/cam/file_sink.cpp b/src/cam/file_sink.cpp\n> index 45213d4a..86e2118c 100644\n> --- a/src/cam/file_sink.cpp\n> +++ b/src/cam/file_sink.cpp\n> @@ -7,11 +7,12 @@\n>\n> #include \n> #include \n> -#include \n> -#include \n> -#include \n> #include \n> #include \n> +#include \n> +\n> +#define PR(...) fmt::print(__VA_ARGS__)\n> +#define EPR(...) fmt::print(stderr, __VA_ARGS__)\n>\n> #include \n>\n> @@ -70,10 +71,10 @@ void FileSink::writeBuffer(const Stream *stream,\n> FrameBuffer *buffer)\n>\n> pos = filename.find_first_of('#');\n> if (pos != std::string::npos) {\n> - std::stringstream ss;\n> - ss << streamNames_[stream] << \"-\" << std::setw(6)\n> - << std::setfill('0') << buffer->metadata().sequence;\n> - filename.replace(pos, 1, ss.str());\n> + auto s = fmt::format(\"{}-{:06}\",\n> + streamNames_[stream],\n> + buffer->metadata().sequence);\n> + filename.replace(pos, 1, s);\n> }\n>\n> fd = open(filename.c_str(), O_CREAT | O_WRONLY |\n> @@ -81,8 +82,7 @@ void FileSink::writeBuffer(const Stream *stream,\n> FrameBuffer *buffer)\n> S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH |\n> S_IWOTH);\n> if (fd == -1) {\n> ret = -errno;\n> - std::cerr << \"failed to open file \" << filename << \": \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"failed to open file {}: {}\\n\", filename,\n> strerror(-ret));\n> return;\n> }\n>\n> @@ -95,20 +95,17 @@ void FileSink::writeBuffer(const Stream *stream,\n> FrameBuffer *buffer)\n> unsigned int length = std::min int>(meta.bytesused, data.size());\n>\n> if (meta.bytesused > data.size())\n> - std::cerr << \"payload size \" << meta.bytesused\n> - << \" larger than plane size \" <<\n> data.size()\n> - << std::endl;\n> + EPR(\"payload size {} larger than plane size {}\\n\",\n> + meta.bytesused, data.size());\n>\n> ret = ::write(fd, data.data(), length);\n> if (ret < 0) {\n> ret = -errno;\n> - std::cerr << \"write error: \" << strerror(-ret)\n> - << std::endl;\n> + EPR(\"write error: {}\\n\", strerror(-ret));\n> break;\n> } else if (ret != (int)length) {\n> - std::cerr << \"write error: only \" << ret\n> - << \" bytes written instead of \"\n> - << length << std::endl;\n> + EPR(\"write error: only {} bytes written instead of\n> {}\\n\",\n> + ret, length);\n> break;\n> }\n> }\n> diff --git a/src/cam/image.cpp b/src/cam/image.cpp\n> index fe2cc6da..73bcf915 100644\n> --- a/src/cam/image.cpp\n> +++ b/src/cam/image.cpp\n> @@ -9,11 +9,14 @@\n>\n> #include \n> #include \n> -#include \n> #include \n> #include \n> #include \n> #include \n> +#include \n> +\n> +#define PR(...) fmt::print(__VA_ARGS__)\n> +#define EPR(...) fmt::print(stderr, __VA_ARGS__)\n>\n> using namespace libcamera;\n>\n> @@ -49,10 +52,8 @@ std::unique_ptr Image::fromFrameBuffer(const\n> FrameBuffer *buffer, MapMode\n>\n> if (plane.offset > length ||\n> plane.offset + plane.length > length) {\n> - std::cerr << \"plane is out of buffer: buffer\n> length=\"\n> - << length << \", plane offset=\" <<\n> plane.offset\n> - << \", plane length=\" << plane.length\n> - << std::endl;\n> + EPR(\"plane is out of buffer: buffer length={},\n> plane offset={}, plane length={}\\n\",\n> + length, plane.offset, plane.length);\n> return nullptr;\n> }\n> size_t &mapLength = mappedBuffers[fd].mapLength;\n> @@ -68,8 +69,8 @@ std::unique_ptr Image::fromFrameBuffer(const\n> FrameBuffer *buffer, MapMode\n> MAP_SHARED, fd, 0);\n> if (address == MAP_FAILED) {\n> int error = -errno;\n> - std::cerr << \"Failed to mmap plane: \"\n> - << strerror(-error) << std::endl;\n> + EPR(\"Failed to mmap plane: {}\\n\",\n> + strerror(-error));\n> return nullptr;\n> }\n>\n> diff --git a/src/cam/kms_sink.cpp b/src/cam/kms_sink.cpp\n> index 7add81a6..823b75e4 100644\n> --- a/src/cam/kms_sink.cpp\n> +++ b/src/cam/kms_sink.cpp\n> @@ -10,10 +10,13 @@\n> #include \n> #include \n> #include \n> -#include \n> #include \n> #include \n> #include \n> +#include \n> +\n> +#define PR(...) fmt::print(__VA_ARGS__)\n> +#define EPR(...) fmt::print(stderr, __VA_ARGS__)\n>\n> #include \n> #include \n> @@ -54,11 +57,9 @@ KMSSink::KMSSink(const std::string &connectorName)\n>\n> if (!connector_) {\n> if (!connectorName.empty())\n> - std::cerr\n> - << \"Connector \" << connectorName << \" not\n> found\"\n> - << std::endl;\n> + EPR(\"Connector {} not found\\n\", connectorName);\n> else\n> - std::cerr << \"No connected connector found\" <<\n> std::endl;\n> + EPR(\"No connected connector found\\n\");\n> return;\n> }\n>\n> @@ -119,7 +120,7 @@ int KMSSink::configure(const\n> libcamera::CameraConfiguration &config)\n> mode.vdisplay ==\n> cfg.size.height;\n> });\n> if (iter == modes.end()) {\n> - std::cerr << \"No mode matching \" << cfg.size << std::endl;\n> + EPR(\"No mode matching {}\\n\", cfg.size);\n> return -EINVAL;\n> }\n>\n> @@ -192,17 +193,12 @@ int KMSSink::configurePipeline(const\n> libcamera::PixelFormat &format)\n> {\n> const int ret = selectPipeline(format);\n> if (ret) {\n> - std::cerr\n> - << \"Unable to find display pipeline for format \"\n> - << format << std::endl;\n> -\n> + EPR(\"Unable to find display pipeline for format {}\\n\",\n> format);\n> return ret;\n> }\n>\n> - std::cout\n> - << \"Using KMS plane \" << plane_->id() << \", CRTC \" <<\n> crtc_->id()\n> - << \", connector \" << connector_->name()\n> - << \" (\" << connector_->id() << \")\" << std::endl;\n> + PR(\"Using KMS plane {}, CRTC {}, connector {} ({})\\n\",\n> + plane_->id(), crtc_->id(), connector_->name(),\n> connector_->id());\n>\n> return 0;\n> }\n> @@ -228,9 +224,8 @@ int KMSSink::start()\n>\n> ret = request->commit(DRM::AtomicRequest::FlagAllowModeset);\n> if (ret < 0) {\n> - std::cerr\n> - << \"Failed to disable CRTCs and planes: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to disable CRTCs and planes: {}\\n\",\n> + strerror(-ret));\n> return ret;\n> }\n>\n> @@ -250,9 +245,7 @@ int KMSSink::stop()\n>\n> int ret = request.commit(DRM::AtomicRequest::FlagAllowModeset);\n> if (ret < 0) {\n> - std::cerr\n> - << \"Failed to stop display pipeline: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to stop display pipeline: {}\\n\",\n> strerror(-ret));\n> return ret;\n> }\n>\n> @@ -312,9 +305,8 @@ bool KMSSink::processRequest(libcamera::Request\n> *camRequest)\n> if (!queued_) {\n> int ret = drmRequest->commit(flags);\n> if (ret < 0) {\n> - std::cerr\n> - << \"Failed to commit atomic request: \"\n> - << strerror(-ret) << std::endl;\n> + EPR(\"Failed to commit atomic request: {}\\n\",\n> + strerror(-ret));\n> /* \\todo Implement error handling */\n> }\n>\n> diff --git a/src/cam/main.cpp b/src/cam/main.cpp\n> index c7f664b9..03615dc9 100644\n> --- a/src/cam/main.cpp\n> +++ b/src/cam/main.cpp\n> @@ -6,10 +6,9 @@\n> */\n>\n> #include \n> -#include \n> -#include \n> #include \n> #include \n> +#include \n>\n> #include \n> #include \n> @@ -78,8 +77,7 @@ int CamApp::init(int argc, char **argv)\n>\n> ret = cm_->start();\n> if (ret) {\n> - std::cout << \"Failed to start camera manager: \"\n> - << strerror(-ret) << std::endl;\n> + fmt::print(\"Failed to start camera manager: {}\\n\", -ret);\n> return ret;\n> }\n>\n> @@ -173,12 +171,12 @@ int CamApp::parseOptions(int argc, char *argv[])\n>\n> void CamApp::cameraAdded(std::shared_ptr cam)\n> {\n> - std::cout << \"Camera Added: \" << cam->id() << std::endl;\n> + fmt::print(\"Camera Added: {}\\n\", cam->id());\n> }\n>\n> void CamApp::cameraRemoved(std::shared_ptr cam)\n> {\n> - std::cout << \"Camera Removed: \" << cam->id() << std::endl;\n> + fmt::print(\"Camera Removed: {}\\n\", cam->id());\n> }\n>\n> void CamApp::captureDone()\n> @@ -193,11 +191,11 @@ int CamApp::run()\n>\n> /* 1. List all cameras. */\n> if (options_.isSet(OptList)) {\n> - std::cout << \"Available cameras:\" << std::endl;\n> + fmt::print(\"Available cameras:\\n\");\n>\n> unsigned int index = 1;\n> for (const std::shared_ptr &cam : cm_->cameras()) {\n> - std::cout << index << \": \" <<\n> cameraName(cam.get()) << std::endl;\n> + fmt::print(\"{}: {}\\n\", cameraName(cam.get()),\n> index);\n> index++;\n> }\n> }\n> @@ -215,12 +213,12 @@ int CamApp::run()\n> index,\n>\n> camera.children());\n> if (!session->isValid()) {\n> - std::cout << \"Failed to create camera\n> session\" << std::endl;\n> + fmt::print(\"Failed to create camera\n> session\\n\");\n> return -EINVAL;\n> }\n>\n> - std::cout << \"Using camera \" <<\n> session->camera()->id()\n> - << \" as cam\" << index << std::endl;\n> + fmt::print(\"Using camera{} as cam{}\\n\",\n> + session->camera()->id(), index);\n>\n> session->captureDone.connect(this,\n> &CamApp::captureDone);\n>\n> @@ -250,7 +248,7 @@ int CamApp::run()\n>\n> ret = session->start();\n> if (ret) {\n> - std::cout << \"Failed to start camera session\" <<\n> std::endl;\n> + fmt::print(\"Failed to start camera session\\n\");\n> return ret;\n> }\n>\n> @@ -259,8 +257,8 @@ int CamApp::run()\n>\n> /* 5. Enable hotplug monitoring. */\n> if (options_.isSet(OptMonitor)) {\n> - std::cout << \"Monitoring new hotplug and unplug events\" <<\n> std::endl;\n> - std::cout << \"Press Ctrl-C to interrupt\" << std::endl;\n> + fmt::print(\"Monitoring new hotplug and unplug events\\n\");\n> + fmt::print(\"Press Ctrl-C to interrupt\\n\");\n>\n> cm_->cameraAdded.connect(this, &CamApp::cameraAdded);\n> cm_->cameraRemoved.connect(this, &CamApp::cameraRemoved);\n> @@ -323,7 +321,7 @@ std::string CamApp::cameraName(const Camera *camera)\n>\n> void signalHandler([[maybe_unused]] int signal)\n> {\n> - std::cout << \"Exiting\" << std::endl;\n> + fmt::print(\"Exiting\");\n> CamApp::instance()->quit();\n> }\n>\n> diff --git a/src/cam/meson.build b/src/cam/meson.build\n> index 5bab8c9e..2b47383d 100644\n> --- a/src/cam/meson.build\n> +++ b/src/cam/meson.build\n> @@ -7,6 +7,8 @@ if not libevent.found()\n> subdir_done()\n> endif\n>\n> +libfmt_dep = dependency('fmt')\n> +\n> cam_enabled = true\n>\n> cam_sources = files([\n> @@ -25,7 +27,7 @@ cam_cpp_args = []\n> libdrm = dependency('libdrm', required : false)\n>\n> if libdrm.found()\n> - cam_cpp_args += [ '-DHAVE_KMS' ]\n> + cam_cpp_args += [ '-DHAVE_KMS', ]\n> cam_sources += files([\n> 'drm.cpp',\n> 'kms_sink.cpp'\n> @@ -38,6 +40,7 @@ cam = executable('cam', cam_sources,\n> libcamera_public,\n> libdrm,\n> libevent,\n> + libfmt_dep,\n> ],\n> cpp_args : cam_cpp_args,\n> install : true)\n> diff --git a/src/cam/options.cpp b/src/cam/options.cpp\n> index 4f7e8691..c9979385 100644\n> --- a/src/cam/options.cpp\n> +++ b/src/cam/options.cpp\n> @@ -7,9 +7,11 @@\n>\n> #include \n> #include \n> -#include \n> -#include \n> #include \n> +#include \n> +\n> +#define PR(...) fmt::print(__VA_ARGS__)\n> +#define EPR(...) fmt::print(stderr, __VA_ARGS__)\n>\n> #include \"options.h\"\n>\n> @@ -390,26 +392,23 @@ KeyValueParser::Options KeyValueParser::parse(const\n> char *arguments)\n> continue;\n>\n> if (optionsMap_.find(key) == optionsMap_.end()) {\n> - std::cerr << \"Invalid option \" << key << std::endl;\n> + EPR(\"Invalid option {}\\n\", key);\n> return options;\n> }\n>\n> OptionArgument arg = optionsMap_[key].argument;\n> if (value.empty() && arg == ArgumentRequired) {\n> - std::cerr << \"Option \" << key << \" requires an\n> argument\"\n> - << std::endl;\n> + EPR(\"Option {} requires an argument\\n\", key);\n> return options;\n> } else if (!value.empty() && arg == ArgumentNone) {\n> - std::cerr << \"Option \" << key << \" takes no\n> argument\"\n> - << std::endl;\n> + EPR(\"Option {} takes no argument\\n\", key);\n> return options;\n> }\n>\n> const Option &option = optionsMap_[key];\n> if (!options.parseValue(key, option, value.c_str())) {\n> - std::cerr << \"Failed to parse '\" << value << \"' as\n> \"\n> - << option.typeName() << \" for option \"\n> << key\n> - << std::endl;\n> + EPR(\"Failed to parse '{}' as {} for option {}\\n\",\n> + value, option.typeName(), key);\n> return options;\n> }\n> }\n> @@ -453,16 +452,16 @@ void KeyValueParser::usage(int indent)\n> argument += \"]\";\n> }\n>\n> - std::cerr << std::setw(indent) << argument;\n> + EPR(\"{:{}}\", argument, indent);\n>\n> for (const char *help = option.help, *end = help; end;) {\n> end = strchr(help, '\\n');\n> if (end) {\n> - std::cerr << std::string(help, end - help\n> + 1);\n> - std::cerr << std::setw(indent) << \" \";\n> + EPR(std::string(help, end - help + 1));\n> + EPR(\"{:{}}\", \"\", indent);\n> help = end + 1;\n> } else {\n> - std::cerr << help << std::endl;\n> + EPR(\"{}\\n\", help);\n> }\n> }\n> }\n> @@ -929,10 +928,10 @@ OptionsParser::Options OptionsParser::parse(int\n> argc, char **argv)\n>\n> if (c == '?' || c == ':') {\n> if (c == '?')\n> - std::cerr << \"Invalid option \";\n> + EPR(\"Invalid option \");\n> else\n> - std::cerr << \"Missing argument for option\n> \";\n> - std::cerr << argv[optind - 1] << std::endl;\n> + EPR(\"Missing argument for option \");\n> + EPR(\"{}\\n\", argv[optind - 1]);\n>\n> usage();\n> return options;\n> @@ -946,8 +945,7 @@ OptionsParser::Options OptionsParser::parse(int argc,\n> char **argv)\n> }\n>\n> if (optind < argc) {\n> - std::cerr << \"Invalid non-option argument '\" <<\n> argv[optind]\n> - << \"'\" << std::endl;\n> + EPR(\"Invalid non-option argument '{}'\\n\", argv[optind]);\n> usage();\n> return options;\n> }\n> @@ -992,14 +990,9 @@ void OptionsParser::usage()\n>\n> indent = (indent + 7) / 8 * 8;\n>\n> - std::cerr << \"Options:\" << std::endl;\n> -\n> - std::ios_base::fmtflags f(std::cerr.flags());\n> - std::cerr << std::left;\n> + EPR(\"Options:\\n\");\n>\n> usageOptions(options_, indent);\n> -\n> - std::cerr.flags(f);\n> }\n>\n> void OptionsParser::usageOptions(const std::list