Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

It is not described in manual.


Additional tests (FreeBSD, Windows XP SP 1):

<?php
	echo 4100000*1.0;
?>

expected result: 4100000
actual result: 4.1E+6

Notice: 
1) it is not float precision problem
2) script is working correctly on php4

It's not working any differently than in PHP 4. Internally it's the same value. Reclassified.

The problem is not internal representation, but float -> string conversion made while 'echo' or while inserting to a string (like $txt="value: $val";).

It is not working same as in php4 (I have tested that scripts with php4 too - the result is correct there: no exponent notation used).

I am running into this same issue.  I just added a comment on bug 43053 which is describing the same issue.

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.

"Floating point numbers can be converted using the exponential notation (4.1E+6)."

fine.. but it wasn't documentation problem

Anyway we have solved it in our scripts, where it was most urgent, by adding special function to convert strings that may contain exponental numbers because this bug - eg. before sending query to mysql (it was easy because we have special class to call databases, but if you use mysql_something functions everywhere you are lucky less...):

	/**
	 * function ConvExponent($str)
	 * This function replaces exponent notation of float values in string
	 */
	function ConvExponent($str)
	{
		return preg_replace('#(\d+)\.(\d+)E(\+|\-)(\d+)#sie', 'sprintf(\'%F\',floatval($0))', $str);
	}