{"id":3856,"date":"2020-08-14T13:10:12","date_gmt":"2020-08-14T07:40:12","guid":{"rendered":"https:\/\/golangbyexamples.com\/?p=3856"},"modified":"2020-08-14T13:21:37","modified_gmt":"2020-08-14T07:51:37","slug":"empty-select-golang","status":"publish","type":"post","link":"https:\/\/golangbyexamples.com\/empty-select-golang\/","title":{"rendered":"Empty select or select with no case in Go (Golang)"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_17 counter-hierarchy counter-decimal ez-toc-light-blue\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" style=\"display: none;\"><i class=\"ez-toc-glyphicon ez-toc-icon-toggle\"><\/i><\/a><\/span><\/div>\n<nav><ul class=\"ez-toc-list ez-toc-list-level-1\"><li class=\"ez-toc-page-1 ez-toc-heading-level-1\"><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/golangbyexamples.com\/empty-select-golang\/#Overview\" title=\"Overview\">Overview<\/a><\/li><li class=\"ez-toc-page-1 ez-toc-heading-level-1\"><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/golangbyexamples.com\/empty-select-golang\/#Code\" title=\"Code\">Code<\/a><\/li><\/ul><\/nav><\/div>\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Overview\"><\/span><strong>Overview<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p class=\"has-medium-font-size\">Select block without any case statement is empty select. The empty select will block forever as there is no case statement&nbsp; to execute. We know that select statement gets blocked until any of the case statement can be executed. It is also one of the way for a goroutine to wait indefinitely. But if this empty select is put in the main goroutine then it will cause a deadlock.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">Let&#8217;s see a program<\/p>\n\n\n\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Code\"><\/span><strong>Code<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">package main\n\nfunc main() {\n    select {}\n}<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\"><strong>Output<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">fatal error: all goroutines are asleep - deadlock!<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">In the above program we have empty select and hence it results in a deadlock that is why you see the output as below<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-\">fatal error: all goroutines are asleep - deadlock!<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Table of Contents OverviewCode Overview Select block without any case statement is empty select. The empty select will block forever as there is no case statement&nbsp; to execute. We know that select&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","footnotes":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false},"categories":[1],"tags":[3,4],"class_list":["post-3856","post","type-post","status-publish","format-standard","hentry","category-tech","tag-go","tag-golang"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.7 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Empty select or select with no case in Go (Golang) - Welcome To Golang By Example<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/golangbyexamples.com\/empty-select-golang\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Empty select or select with no case in Go (Golang) - Welcome To Golang By Example\" \/>\n<meta property=\"og:description\" content=\"Table of Contents OverviewCode Overview Select block without any case statement is empty select. 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