{"id":13942,"url":"https://patchwork.libcamera.org/api/patches/13942/?format=json","web_url":"https://patchwork.libcamera.org/patch/13942/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20210926212108.22510-3-laurent.pinchart@ideasonboard.com>","date":"2021-09-26T21:21:08","name":"[libcamera-devel,3/3] Documentation: application-developer: Add camera detection check","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"93ec595965194841a61920c6836b437e24c5d73b","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/?format=json","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/13942/mbox/","series":[{"id":2571,"url":"https://patchwork.libcamera.org/api/series/2571/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=2571","date":"2021-09-26T21:21:06","name":"[libcamera-devel,1/3] Documentation: application-developer: Make global variable static","version":1,"mbox":"https://patchwork.libcamera.org/series/2571/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/13942/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/13942/checks/","tags":{},"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 BECA8BDC71\n\tfor ;\n\tSun, 26 Sep 2021 21:21:22 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 192AB69196;\n\tSun, 26 Sep 2021 23:21:21 +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 B49BE6918C\n\tfor ;\n\tSun, 26 Sep 2021 23:21:17 +0200 (CEST)","from pendragon.lan (62-78-145-57.bb.dnainternet.fi [62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 565C0EF\n\tfor ;\n\tSun, 26 Sep 2021 23:21:17 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"bgRMjNTY\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1632691277;\n\tbh=TR+ZJaJoSYN3LVeVnSyz1vepTTzQqgphN7g9/FMDlEs=;\n\th=From:To:Subject:Date:In-Reply-To:References:From;\n\tb=bgRMjNTYmDWt44Yyxblp5LGxjSYwkTfAcnBwBfIdpYztUu7fL4GkYBVnMAUxSc+EF\n\t3MqoPNQiPI1V3BxwRECjuJnsz91/EbFnHnr9YiFLrU8fGhoiuEwoXcj8q+PCtt0Vkc\n\tOjO/XAoUvSoLl7qVZdirLNNyjunbtXpz1G5OmS/A=","From":"Laurent Pinchart ","To":"libcamera-devel@lists.libcamera.org","Date":"Mon, 27 Sep 2021 00:21:08 +0300","Message-Id":"<20210926212108.22510-3-laurent.pinchart@ideasonboard.com>","X-Mailer":"git-send-email 2.32.0","In-Reply-To":"<20210926212108.22510-1-laurent.pinchart@ideasonboard.com>","References":"<20210926212108.22510-1-laurent.pinchart@ideasonboard.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH 3/3] Documentation: application-developer:\n\tAdd camera detection check","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\" "},"content":"The simple-cam application has a check to ensure that at least one\ncamera is present before attempting to access the first camera, to avoid\na crash. Update the application developer's guide accordingly.\n\nSigned-off-by: Laurent Pinchart \n---\n Documentation/guides/application-developer.rst | 9 ++++++++-\n 1 file changed, 8 insertions(+), 1 deletion(-)","diff":"diff --git a/Documentation/guides/application-developer.rst b/Documentation/guides/application-developer.rst\nindex 41a7d88369be..11d3df15825b 100644\n--- a/Documentation/guides/application-developer.rst\n+++ b/Documentation/guides/application-developer.rst\n@@ -109,9 +109,16 @@ the Camera Manager reports as available to applications.\n Camera devices are stored by the CameraManager in a list accessible by index, or\n can be retrieved by name through the ``CameraManager::get()`` function. The\n code below retrieves the name of the first available camera and gets the camera\n-by name from the Camera Manager.\n+by name from the Camera Manager, after making sure that at least one camera is\n+available.\n \n .. code:: cpp\n+ if (cm->cameras().empty()) {\n+ std::cout << \"No cameras were identified on the system.\"\n+ << std::endl;\n+ cm->stop();\n+ return EXIT_FAILURE;\n+ }\n \n std::string cameraId = cm->cameras()[0]->id();\n camera = cm->get(cameraId);\n","prefixes":["libcamera-devel","3/3"]}