#37528 [NEW]: rand() weakness

From: lunter at interia dot pl Operating system: WinXP PHP version: 5.1.4 PHP Bug Type: Math related Bug description: rand() weakness Description: ------------ rand() weakness. example (reproduce code): rand generate pattern instead of noise Reproduce code: --------------- <? $i=imagecreatetruecolor(1024,768); for($y=0;$y<768;$y++){ for($x=0;$x<1024;$x++){ $c=rand(0,1)*255; imagesetpixel($i,$x,$y,($c<<16)+($c<<8)+$c); } } header('Content-type: image/png'); imagepng($i); ?> Expected result: ---------------- noise Actual result: -------------- pattern -- Edit bug report at http://bugs.php.net/?id=37528&edit=1 -- Try a CVS snapshot (PHP 4.4): http://bugs.php.net/fix.php?id=37528&r=trysnapshot44 Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=37528&r=trysnapshot52 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=37528&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=37528&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=37528&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=37528&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=37528&r=needscript Try newer version: http://bugs.php.net/fix.php?id=37528&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=37528&r=support Expected behavior: http://bugs.php.net/fix.php?id=37528&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=37528&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=37528&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=37528&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=37528&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=37528&r=dst IIS Stability: http://bugs.php.net/fix.php?id=37528&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=37528&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=37528&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=37528&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=37528&r=mysqlcfg