The performance cost of C++'s std::endl vs. a simple newline

Description

A two-panel 'Barbenheimer' meme. The left panel features a brightly colored, cheerful image of Barbie with the text '\n'. The right panel shows a serious, black-and-white image of J. Robert Oppenheimer with the text 'std::endl'. This meme visually contrasts the simple, efficient newline character ('\n') with the more complex and performance-heavy 'std::endl' manipulator in C++. The technical joke is that 'std::endl' not only adds a newline but also flushes the output stream, an often unnecessary operation that can impact performance. The meme humorously portrays '\n' as fun and carefree (Barbie) and 'std::endl' as overly serious and dramatic (Oppenheimer), reflecting a common C++ programming debate

Common Tags

CPlusPlusStandardLibrary LanguageQuirks PerformanceTradeoffs Syntax DeveloperHumor

Comments

Anonymous ★ Top Pick 'std::endl' is for when you want to end a line with the dramatic weight of creating a new world, only to immediately destroy it with an unnecessary buffer flush

Anonymous ★ Top Pick

'std::endl' is for when you want to end a line with the dramatic weight of creating a new world, only to immediately destroy it with an unnecessary buffer flush
Anonymous

\n politely waits for the I/O buffer; std::endl flushes like it’s reenacting Trinity - perfect if you want a mushroom cloud in your flame graph
Anonymous

After 20 years in the industry, you realize the real atomic bomb was the unnecessary buffer flushes in your logging framework that brought down production at 3am because someone thought std::endl was just a fancy way to write '\n'
Anonymous

The eternal C++ dilemma: do you want your output fast and breezy with \n, or do you prefer the sophisticated, buffer-flushing gravitas of std::endl? Sure, std::endl looks more professional in code reviews, but when you're logging in a tight loop and wondering why your application is slower than a Python script, you'll realize that sometimes the simple backslash-n is the hero we need, not the manipulator we deserve. Remember: premature flushing is a performance problem
Anonymous

std::endl: the iostream manipulator that turns printing into a sync boundary - fine for TTYs, brutal for hot loops
Anonymous

Barbie's '\n' stays buffered and svelte; Bogey's std::endl flushes like it's allergic to throughput
Anonymous

Senior lesson: \n ends a line; std::endl ends your throughput - unless you enjoy a syscall per log line
@AndoroidP 3y

For all of those non-competitive programmers out there, \n is much faster than endl.
@Araalith 3y

It depends on the buffering settings.
1. @CcxCZ 3y
  
  TBF libc stdio is bit of a mess. I know people who opt to not use it to make their binaries thinner. (we're talking kilobytes w/ static linking)
  
  @azizhakberdiev 3y
  
  some companies even require doing this, cuz they don't put trust even on built-in features
valentyn 3y

when do you need it t
@phpzapecanus 3y

Wtf I'm only touched c++ and already receiving this meme
1. @SamsonovAnton 3y
  
  You can't touch *this.