Doc #65852 [Ver->Csd]: Wrong documentation about NAN comparison

Edit report at https://bugs.php.net/bug.php?id=65852&edit=1 ID: 65852 Updated by: cmb@php.net Reported by: chalkerx at gmail dot com Summary: Wrong documentation about NAN comparison -Status: Verified +Status: Closed Type: Documentation Problem Package: Documentation problem Operating System: Linux PHP Version: 5.5.4 Assigned To: cmb Block user comment: N Private report: N New Comment: This bug has been fixed in the documentation's XML sources. Since the online and downloadable versions of the documentation need some time to get updated, we would like to ask you to be a bit patient. Thank you for the report, and for helping us make our documentation better. Previous Comments: ------------------------------------------------------------------------ [2017-01-28 16:32:56] cmb@php.net Automatic comment from SVN on behalf of cmb Revision: http://svn.php.net/viewvc/?view=revision&amp;revision=341793 Log: Fix #65852: Wrong documentation about NAN comparison ------------------------------------------------------------------------ [2017-01-28 16:29:56] cmb@php.net > I believe the wording is just not precise and "value" means > "numeric value" in this case. Even comparing non-numeric strings with NAN yields FALSE[1]. The sole exception appears to be TRUE[2]. [1] <https://3v4l.org/orCLn> [2] <https://3v4l.org/VY7oe> ------------------------------------------------------------------------ [2013-10-09 09:23:36] phpmpan at mpan dot pl As documentation states, conversion from NaN to boolean should yield TRUE, and hence TRUE == TRUE will be TRUE too. I believe the wording is just not precise and "value" means "numeric value" in this case. Of course this needs to be fixed. ------------------------------------------------------------------------ [2013-10-07 17:48:03] chalkerx at gmail dot com Whoops, browser-saved title from the old bug. ------------------------------------------------------------------------ [2013-10-07 17:46:00] chalkerx at gmail dot com Description: ------------ http://www.php.net/manual/en/types.comparisons.php states: > Some numeric operations can result in a value represented by the constant NAN. Any loose or > strict comparisons of this value against any other value, including itself, will have a result of > FALSE But that is invalid, because NAN loosely equals to boolean true. Test script: --------------- var_dump(sqrt(-1)); var_dump(sqrt(-1) == true); Expected result: ---------------- As per documentation, the result should be: double(NAN) bool(false) The documentation should be consistent with what actually happens. Actual result: -------------- double(NAN) bool(true) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=65852&edit=1