#35662 [Opn->Fbk]: The 'rand()' function returns only few different values

ID: 35662 Updated by: sniper@php.net Reported By: jullrich at sans dot org -Status: Open +Status: Feedback Bug Type: *Math Functions Operating System: Linux 2.6 (RedHat) PHP Version: 4.4.1 New Comment: Please try using this CVS snapshot: http://snaps.php.net/php5.1-latest.tar.gz For Windows: http://snaps.php.net/win32/php5.1-win32-latest.zip Previous Comments: ------------------------------------------------------------------------ [2005-12-13 20:53:53] jullrich at sans dot org Description: ------------ The 'rand' function is far from random. For example, the following code: <?= rand(10000000000,99999999999); ?> only generates values that start with '12','13' or '14'. Out of 1500 times the function is called, only approx. 1000 different values are generated. Reproduce code: --------------- <?= rand(10000000000,99999999999); ?> Expected result: ---------------- somewhat random numbers between 10000000000 and 99999999999. Actual result: -------------- all numbers are in the range from 120000000000 to 150000000000 and frequently repeat (about 25% of the numbers are repeats). Sample: 1379409636 1275750426 1248288483 1398136354 1404047798 1292410973 1405794269 1278267510 1225653649 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=35662&edit=1