Bug #66959 [Com]: bcadd with floats fails

Edit report at https://bugs.php.net/bug.php?id=66959&edit=1 ID: 66959 Comment by: trainmaster at gmx dot net Reported by: james dot turner dot phpninja at gmail dot com Summary: bcadd with floats fails Status: Verified Type: Bug Package: BC math related Operating System: Ubuntu 13 PHP Version: 5.5.10 Block user comment: N Private report: N New Comment: Some more examples (Output for 5.2.2 - 5.6.0alpha3): var_dump(bcadd(0,-0.00555555,9)); // string(12) "-0.005555550" var_dump((string) -0.00555555); // string(11) "-0.00555555" var_dump(bcadd(0,-0.00055555,9)); // string(12) "-0.000555550" var_dump((string) -0.00055555); // string(11) "-0.00055555" var_dump(bcadd(0,-0.00005555,9)); // string(11) "0.000000000" var_dump((string) -0.00005555); // string(10) "-5.555E-05" var_dump(bcadd(0,-0.00000555,9)); // string(11) "0.000000000" var_dump((string) -0.00000555); // string(9) "-5.55E-06" var_dump(bcadd(0,-0.00000055,9)); // string(11) "0.000000000" var_dump((string) -0.00000055); // string(8) "-5.5E-07" var_dump(bcadd(0,-0.00000005,9)); // string(11) "0.000000000" var_dump((string) -0.00000005); // string(6) "-5E-08" Previous Comments: ------------------------------------------------------------------------ [2014-04-02 21:56:23] trainmaster at gmx dot net @nikic See bwoebi's example when string arguments are passed. The problem seems to be the scientific notation. ------------------------------------------------------------------------ [2014-04-01 13:47:04] nikic@php.net BCMath explicitly works with strings, not floating point numbers. In https://bugs.php.net/bug.php?id=55160 Mike made the decision that we should not have extra support for passing floats to bc functions. ------------------------------------------------------------------------ [2014-04-01 13:17:45] bwoebi@php.net Actually the bcmath extension doesn't like scientific notation. var_dump((string)-0.00000545); string(8) "-5.45E-6" and var_dump(bcadd("-0.05648055","-5.45E-6",9)); string(12) "-0.056480550" ------------ Would be great if someone could make bcmath support scientific notation... ------------------------------------------------------------------------ [2014-03-26 12:08:25] james dot turner dot phpninja at gmail dot com Description: ------------ bcadd does not appear to work for certain numbers when using floats as inputs rather than strings. This is particularly apparent if you json_decode from json to php variables where floats are generated as you get floats not strings. Any attempt at casting to a string produces the same output. I can only assume it's actually an issue with float->string casting. Test script: --------------- $a = -0.05648055; $b = -0.00000545; $c = bcadd($a,$b,9); $d = $a+$b; echo $c; // => -0.05648055 <- WRONG echo $d; // => -0.056486 <- CORRECT assert($c == -0.056486); Expected result: ---------------- assert ok Usage of string literals for the negative floats works fine. However casting the floats to strings fails (which is why I assume that bcadd also has the same problem in casting to strings before computation). Actual result: -------------- assert fail ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=66959&edit=1