ID: 34179
Comment by: yaXay at gmx dot net
Reported By: pww8 at cornell dot edu
Status: Open
Bug Type: Feature/Change Request
Operating System: Linux 2.4.9
PHP Version: 5.0.4
New Comment:
As far as I know 1/0 is undefined (lim x->0 (1/x) is inf.), as well as
1.0e300*1.0e300 simply produces an overflow. Of course that is just a
technicality, but still..
Regarding devide by zero and overflows, I would go even further and
throw an exception, because that is what they are: exceptions. Nobody
divides by zero or generates overflows on purpose. They usually occur
on erroneous user input. Throwing exceptions would of course force the
programmer to be more aware of this issue, since exceptions have a
habit of stopping execution when they are not caught. Howerver I find
it good to force the programmer to produce clean code, I mean, what is
the downside??
Sincerely,
Benjamin Schulz
Previous Comments:
------------------------------------------------------------------------
[2005-08-18 00:44:16] pww8 at cornell dot edu
Description:
------------
It appears floating-point infinity (INF) is not returned from divide by
zero (in PHP 5.0.0). Instead a warning is given and Boolean FALSE is
returned.
This is no doubt well-known behavior to most users, probably would be
confusing to change the default. But it would be useful for me to
throw a switch or set an .ini file variable to some non-default state,
and get the correct answer instead of FALSE.
Note that you can get INF from multiply, e.g. 1.0e300*1.0e300 [Linux on
Intel]. Might also be nice to get INF when it is the correct answer!
Reproduce code:
---------------
// Expected result would be after I set some non-default
// floating point handling mode above...
$varxx = 1.0 / 0.0;
$if (isset($varxx))
{ boolean = is_bool($varxx) ? "Boolean" : "Not Boolean" ;
print "\nSET $varxx $boolean";
}
else
{ print "\nNOT SET"; }
print "\nanother test, exp of very large number is : " . exp(1.0e300);
print "\ntry for infinity using * : " . 1.0e300*1.0e300;
Expected result:
----------------
SET INF Not Boolean
another test, exp of very large number is : INF
try for infinity using * : INF
Actual result:
--------------
SET Boolean
another test, exp of very large number is : INF
try for infinity using * : INF
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/?id=34179&edit=1
