--- title: Best performance of a C++ singleton | daily.dev description: A deep dive into C++ singleton performance, comparing block-local static variables versus static data members, and user-declared versus user-defined... canonical: https://daily.dev/posts/best-performance-of-a-c-singleton-xezmghtqp twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Best performance of a C++ singleton | daily.dev og:description: A deep dive into C++ singleton performance, comparing block-local static variables versus static data members, and user-declared versus user-defined... og:url: https://daily.dev/posts/best-performance-of-a-c-singleton-xezmghtqp og:image: https://api.daily.dev/og/posts/xEzmghtqp.png og:image:alt: Best performance of a C++ singleton og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Best performance of a C++ singleton **[Andreas Fertig](https://daily.dev/sources/andreasfertig)** · 5 min read · 0 upvotes · 0 comments ## Summary A deep dive into C++ singleton performance, comparing block-local static variables versus static data members, and user-declared versus user-defined constructors. When a user-defined constructor is required, the block-local static approach forces the compiler to insert guard variables and locking calls (__cxa_guard_acquire/__cxa_guard_release), adding overhead. Using a private static data member avoids these locks entirely. If the default constructor can be defaulted, both approaches produce equivalent assembly. The recommendation: use static data members when a custom constructor is needed, and block-local statics otherwise. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Singleton done right in C\+\+](https://daily.dev/posts/singleton-done-right-in-c--4mg4cpfod) · C\+\+ · 3 upvotes · 0 comments --- Tags: [#assembly](https://daily.dev/tags/assembly), [#c++](https://daily.dev/tags/c++), [#performance](https://daily.dev/tags/performance) [View this post on daily.dev](https://daily.dev/posts/best-performance-of-a-c-singleton-xezmghtqp) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Best performance of a C++ singleton","url":"https://daily.dev/posts/best-performance-of-a-c-singleton-xezmghtqp","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/best-performance-of-a-c-singleton-xezmghtqp"},"datePublished":"2026-03-03T07:49:27.870Z","dateModified":"2026-03-15T06:05:03.213Z","description":"A deep dive into C++ singleton performance, comparing block-local static variables versus static data members, and user-declared versus user-defined...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/6798b8ac0cc3d24c0fc1b7a95a97cb03?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/6798b8ac0cc3d24c0fc1b7a95a97cb03?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Andreas Fertig","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Andreas Fertig","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/3721178188164a95922fd3c9970bcab7","url":"https://daily.dev/sources/andreasfertig"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/best-performance-of-a-c-singleton-xezmghtqp","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"assembly,c++,performance","timeRequired":"PT5M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Andreas Fertig","item":"https://daily.dev/sources/andreasfertig"},{"@type":"ListItem","position":3,"name":"Best performance of a C++ singleton"}]} ```