Bug #79443 [Com]: round with precision is not rounding

Edit report at https://bugs.php.net/bug.php?id=79443&edit=1 ID: 79443 Comment by: bugreports at gmail dot com Reported by: info at globules dot io Summary: round with precision is not rounding Status: Not a bug Type: Bug Package: *General Issues Operating System: Windows 10 x64 PHP Version: 7.4.4 Assigned To: cmb Block user comment: N Private report: N New Comment: > I am on Windows 10 Pro x64 and ran this from command prompt yeah, but you didn't mangle the "precision" config (look at the subejct) garbage in, garbage out and so we are at: Floating point values have a limited precision. Hence a value might not have the same string representation after any processing. That also includes writing a floating point value in your script and directly printing it without any mathematical operations php -n -d precision=100 -r "echo round(-80.0035326999999938, 6);" -80.00353300000000444924808107316493988037109375 Previous Comments: ------------------------------------------------------------------------ [2020-04-01 16:40:27] tiffany@php.net I am on Windows 10 Pro x64 and ran this from command prompt. C:\Users\Tylae>php -r "echo round(-80.0035326999999938, 6);" -80.003533 ------------------------------------------------------------------------ [2020-04-01 16:10:18] info at globules dot io How is this not a bug? This is the exact code. I'm rounding with precision, it works on Linux, doesn't work on Windows. ------------------------------------------------------------------------ [2020-04-01 16:06:34] info at globules dot io Yes I have posted the exact code. ------------------------------------------------------------------------ [2020-04-01 15:48:07] danack@php.net Mr Info Are you sure that code you posted is actually the code that's producing that output? https://3v4l.org/v9k54 ------------------------------------------------------------------------ [2020-04-01 15:44:09] cmb@php.net Floating point values have a limited precision. Hence a value might not have the same string representation after any processing. That also includes writing a floating point value in your script and directly printing it without any mathematical operations. If you would like to know more about "floats" and what IEEE 754 is, read this: http://www.floating-point-gui.de/ Thank you for your interest in PHP. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=79443 -- Edit this bug report at https://bugs.php.net/bug.php?id=79443&edit=1