--- title: Watch Your Threads Fall Into Perfect Sync #cpp... description: C++20 introduced osyncstream, a tool for synchronized console output in multithreaded programs. It works by buffering output internally and then atomically... canonical: https://daily.dev/posts/watch-your-threads-fall-into-perfect-sync-cpp-concurrency-cpp20-ycvhjycgy twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Watch Your Threads Fall Into Perfect Sync #cpp #concurrency #cpp20 | daily.dev og:description: C++20 introduced osyncstream, a tool for synchronized console output in multithreaded programs. It works by buffering output internally and then atomically... og:url: https://daily.dev/posts/watch-your-threads-fall-into-perfect-sync-cpp-concurrency-cpp20-ycvhjycgy og:image: https://api.daily.dev/og/posts/ycVhJycgy.png og:image:alt: Watch Your Threads Fall Into Perfect Sync #cpp #concurrency #cpp20 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. # Watch Your Threads Fall Into Perfect Sync #cpp #concurrency #cpp20 **[C\+\+Online](https://daily.dev/sources/cpponline)** · 1 min read · 0 upvotes · 0 comments ## Summary C++20 introduced osyncstream, a tool for synchronized console output in multithreaded programs. It works by buffering output internally and then atomically transferring the entire buffer to the underlying stream, preventing the interleaved/broken output common when multiple threads write to cout simultaneously. It can be used via scoped objects (flushing on destructor) or temporary objects (flushing at end of line). The underlying syncbuf API exposes methods like emit, get_wrapped, set_emit_on_sync, and sync. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [How we interfaced single-threaded C\+\+ with multi-threaded Rust](https://daily.dev/posts/how-we-interfaced-single-threaded-c-with-multi-threaded-rust-w9nznwtme) · Hacker News · 5 upvotes · 0 comments --- Tags: [#c++](https://daily.dev/tags/c++) [View this post on daily.dev](https://daily.dev/posts/watch-your-threads-fall-into-perfect-sync-cpp-concurrency-cpp20-ycvhjycgy) ```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":"Watch Your Threads Fall Into Perfect Sync #cpp #concurrency #cpp20","url":"https://daily.dev/posts/watch-your-threads-fall-into-perfect-sync-cpp-concurrency-cpp20-ycvhjycgy","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/watch-your-threads-fall-into-perfect-sync-cpp-concurrency-cpp20-ycvhjycgy"},"datePublished":"2026-07-05T07:25:45.909Z","dateModified":"2026-07-05T07:26:13.172Z","description":"C++20 introduced osyncstream, a tool for synchronized console output in multithreaded programs. 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