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Subject: [RFC] [DISCUSSION] More precise float value
From: yohgaki@ohgaki.net (Yasuo Ohgaki)

Hi all,

IEEE 754 double cannot express exact float values. That said,
float values expressed by json/serialize/var_export/echo/print
are not precise enough in many cases.

Issues:
 - json_encode() uses EG(precision)=14 that truncates float values.
echo()/print()
   does this as well.
 - large EG(precision)/PG(serialize_precision) prints meaningless values.

This RFC proposes zend_dtoa()'s 0 mode support which rounds float value
to nearest value.

https://wiki.php.net/rfc/precise_float_value
https://github.com/php/php-src/pull/1455

This change is simple enough for PHP 7.0. IMO.
Comments/suggestions are appreciated!

Regards,

--
Yasuo Ohgaki
yohgaki@ohgaki.net