From: ringtail dot jack at gmail dot com
Operating system: Linux Mint 11
PHP version: 5.3.18
Package: Math related
Bug Type: Bug
Bug description:Unexpected output when using log() function results
Description:
------------
Using the modulus operator with the results of a call to log(N, 10)
produces unexpected results when N % 3 = 0.
Other arithmetic operations result as expected.
Equivalent operations using a call to log10(N) rather than log(N, 10)
result as expected.
Using echo to display log() results will display the correct value.
However, passing it through printf or sprintf will print or return the
correct value minus 1.
[ Note: phpinfo() on my computer reports a PHP version of
5.3.5-1ubuntu7.11. I selected what seemed to be the closest version
available in the web form. ]
Test script:
---------------
$exp = 15;
$n = pow(10, $exp);
$base = 10;
$log = log($n, $base);
echo "log: ".$log."\n";
echo "log % 3: ".$log % 3 ."\n";
echo "log via sprintf: ".sprintf('%d', $log)."\n";
$log = log10($n);
echo "log10: ".$log."\n";
echo "log10 % 3: ".$log % 3 ."\n";
echo "log10 via sprintf: ".sprintf('%d', $log)."\n";
Expected result:
----------------
log: 15
log % 3: 0
log via sprintf: 15
log10: 15
log10 % 3: 0
log10 via sprintf: 15
Actual result:
--------------
log: 15
log % 3: 2
log via sprintf: 14
log10: 15
log10 % 3: 0
log10 via sprintf: 15
--
Edit bug report at https://bugs.php.net/bug.php?id=63476&edit=1
--
Try a snapshot (PHP 5.4):
https://bugs.php.net/fix.php?id=63476&r=trysnapshot54
Try a snapshot (PHP 5.3):
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Try a snapshot (trunk):
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Fixed in SVN: https://bugs.php.net/fix.php?id=63476&r=fixed
Fixed in release: https://bugs.php.net/fix.php?id=63476&r=alreadyfixed
Need backtrace: https://bugs.php.net/fix.php?id=63476&r=needtrace
Need Reproduce Script: https://bugs.php.net/fix.php?id=63476&r=needscript
Try newer version: https://bugs.php.net/fix.php?id=63476&r=oldversion
Not developer issue: https://bugs.php.net/fix.php?id=63476&r=support
Expected behavior: https://bugs.php.net/fix.php?id=63476&r=notwrong
Not enough info:
https://bugs.php.net/fix.php?id=63476&r=notenoughinfo
Submitted twice:
https://bugs.php.net/fix.php?id=63476&r=submittedtwice
register_globals: https://bugs.php.net/fix.php?id=63476&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=63476&r=php4
Daylight Savings: https://bugs.php.net/fix.php?id=63476&r=dst
IIS Stability: https://bugs.php.net/fix.php?id=63476&r=isapi
Install GNU Sed: https://bugs.php.net/fix.php?id=63476&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=63476&r=float
No Zend Extensions: https://bugs.php.net/fix.php?id=63476&r=nozend
MySQL Configuration Error: https://bugs.php.net/fix.php?id=63476&r=mysqlcfg
