#6019 [Ana->Csd]: document precision of floating point values

ID: 6019 Updated by: tony2001@php.net Reported By: thomas at netropolis dot dk -Status: Analyzed +Status: Closed Bug Type: Feature/Change Request Operating System: NT4.0 PHP Version: 4.0.1pl2 New Comment: See http://php.net/float Previous Comments: ------------------------------------------------------------------------ [2002-04-28 18:16:57] jimw@php.net updating summary. ------------------------------------------------------------------------ [2000-08-08 10:34:55] hholzgra@php.net the precisions are machine-/build-dependant so we can't document them in the manual maybe we can add a section to phpinfo() and/or some constants as in limits.h for MIN/MAX values for integer and float values (passed on to feature request) ------------------------------------------------------------------------ [2000-08-08 09:37:36] waldschrott@php.net I think this limitation isn´t mentioned anywhere clearly, transforming into docu bug In fact I don´t know where to look for it and I think the php.ini precision settings has nothing to do with it... ------------------------------------------------------------------------ [2000-08-08 09:25:26] waldschrott@php.net verified, replacing == with === in the third block will produce 0, what is correct for any reason the comparison is done corretly withing strings, I think you won´t have to switch to bcmaths functions for these tiny doubles, using var_dump() reveals that they´re correctly stored in $GLOABLS resumé: PHP performs return only 0,2,4 differences not 1,3,5 dealing with large numbers example: echo 9834567891230000-9834567891229999; // return2 s, should 1 echo 9834567891230000-9834567891230001; // returns 0, should -1 and so on ------------------------------------------------------------------------ [2000-08-08 09:07:23] stas@php.net 1. Use === when you are interested in string-to-string comparison. 2. PHP has precision limits, if you need more precision please use bc extension. ------------------------------------------------------------------------ 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 http://bugs.php.net/6019 -- Edit this bug report at http://bugs.php.net/?id=6019&edit=1