ID: 25562
Updated by: [email]hellyphp.net[/email]
Reported By: daseymour at 3hc dot org
-Status: Open
+Status: Bogus
Bug Type: Math related
Operating System: [Win 2000 SP4] and [Win XP SP1]
PHP Version: 4.3.3
New Comment:

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

Floating point values are handled with a limited precision.


Previous Comments:
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[2003-09-16 15:34:29] daseymour at 3hc dot org

Description:
------------
When I convert a large float value to a string and then back to a
float, the original and the resulting values are not equal.

Note: I looked for this error in the bug list, but did not find one
with the current stable release of PHP (4.3.3).

Thanks in advance.

Reproduce code:
---------------
// Create some large number
$testStart = (float) unserialize("d:1125899906842624;");
// Output value
echo "Before string conversion: $testStart <br>\n";
// Convert value to string
$testString = (string) $testStart;
// Output string
echo "After string conversion: $testString <br>\n";
// Convert string back to a value
$testEnd = (float) $testString;
// Output value
echo "After float conversion: $testEnd <br>\n";
// Compare the two values
if( $testStart == $testEnd ) {
echo "<br>\nThe two values are equal.<br>\n";
} else {
echo "<br>\nThe two values appear to be the same, but are <u>not</u>
equal!<br>\n";
};

Expected result:
----------------
I expect to see "The two values are equal."

Actual result:
--------------
I am getting "The two values appear to be the same, but are not equal!"


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