Doc #66866 [Opn->Nab]: Same output for float numbers when using variable handling functions

Edit report at https://bugs.php.net/bug.php?id=66866&edit=1

 ID:                 66866
 Updated by:         [email protected]
 Reported by:        jan dot kahoun at heureka dot cz
 Summary:            Same output for float numbers when using variable
                     handling functions
-Status:             Open
+Status:             Not a bug
 Type:               Documentation Problem
 Package:            Variables related
 Operating System:   CentOS release 6.4 (Final)
 PHP Version:        Irrelevant
 Block user comment: N
 Private report:     N

 New Comment:

Since PHP 7.1 var_dump and the like also output the float in full precision. This ini option is documented here: https://www.php.net/manual/en/ini.core.php#ini.precision


Previous Comments:
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[2018-08-23 18:57:37] php at sam002 dot net

This is really misleading.The 'serialize_precision', the default value was recently made '-1'. Also need for 'precision'.

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[2014-03-09 18:26:54] jan dot kahoun at heureka dot cz

Yes, that's true. So maybe it will be better to have same value for setting the "precision" and "serialize_precision" at default? I realy don't know why is better to have lower precision when displaying value? What are the usecases? I thought that for precision purpouses, there are relevant functions like round(), format_number(), ceil() and floor(). 
I'm not the only one who is facing with this strange behaviour. ;-)

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[2014-03-09 18:10:37] [email protected]

echo/print() are used for debugging too all over the place. Having print_r() show a different value would lead to the exact same confusion. The best we can do is do a better job explaining the precision settings on the relevant doc pages.

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[2014-03-09 17:58:23] jan dot kahoun at heureka dot cz

But functions var_dump() and print_r() are often used for debuging purpouses. So if you want to see what is actually in the variable you will not expect the rounded value. This is realy confusing.

I think, that this should be at least mentioned on the all doc pages of the functions var_dump(), print_r() and var_export().

Thank you.

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[2014-03-09 17:31:44] [email protected]

var_export() is fundamentally different from print_r() and var_dump() in that it is often used to read data back in. As such it is closer to serialize() than the others which are display-only functions. For display purposes PHP has the 'precision' ini setting and for serialize-purposes we have serialize_precision. In you script, if you do:

echo ini_set('precision',ini_get('serialize_precision'));

At the top you should get the same value for all three.

But yes, this probably should be mentioned on the var_export doc page.

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