From: bdew at druzya dot org Operating system: windows xp sp2 PHP version: 5.2.4 PHP Bug Type: Math related Bug description: nonrandom rand() results in lower bits
Description: ------------ Under windows xp cli version, rand() seems to return cycling values in lower bits. If i use rand(x,y) the bug does happen only when max_rand+2>y>max_rand+2 mt_rand() is unaffected Tested same code under linux cli and the bug doesn't happen. possibly related to http://bugs.php.net/bug.php?id=43108 Reproduce code: --------------- $a=rand() & 0xff; for ($k=0;$k<10;$k++) { $i=0; do { $i++; $b=rand() & 0xff; } while ($a!=$b); echo("cycle: $i\n"); }; Expected result: ---------------- 10 lines with "cycle: x", x being different every line Actual result: -------------- cycle: 256 cycle: 256 cycle: 256 cycle: 256 cycle: 256 cycle: 256 cycle: 256 cycle: 256 cycle: 256 cycle: 256 every time -- Edit bug report at http://bugs.php.net/?id=43171&edit=1 -- Try a CVS snapshot (PHP 4.4): http://bugs.php.net/fix.php?id=43171&r=trysnapshot44 Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=43171&r=trysnapshot52 Try a CVS snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=43171&r=trysnapshot53 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=43171&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=43171&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=43171&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=43171&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=43171&r=needscript Try newer version: http://bugs.php.net/fix.php?id=43171&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=43171&r=support Expected behavior: http://bugs.php.net/fix.php?id=43171&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=43171&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=43171&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=43171&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=43171&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=43171&r=dst IIS Stability: http://bugs.php.net/fix.php?id=43171&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=43171&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=43171&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=43171&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=43171&r=mysqlcfg
