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Bug #79861 bug found in php 5.3, 5.4. 7.0, 7.1, 7.2
Submitted: 2020-07-14 19:35 UTC Modified: 2020-07-14 19:39 UTC
From: BardoQi at gmail dot com Assigned:
Status: Not a bug Package: Unknown/Other Function
PHP Version: 7.2.32 OS: windwos 10, contos7
Private report: No CVE-ID: None
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From: BardoQi at gmail dot com
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 [2020-07-14 19:35 UTC] BardoQi at gmail dot com 
Description:
------------
The return value of expression /(4.1-0.1 == 4.0)/ should be true, but infact false!!

Test script:
---------------
		echo(4.1-0.1 == 4.0);
		echo(4.1-0.1 == 4);
		echo((4.1-0.1) == 4.0);
		echo((4.1-0.1) == 4);

Expected result:
----------------
1111

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 [2020-07-14 19:39 UTC] requinix@php.net
-Status: Open +Status: Not a bug
 [2020-07-14 19:39 UTC] requinix@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.
 
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