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Posted by Jerry Stuckle on 11/18/61 11:41
d wrote:
> "Jerry Stuckle" <jstucklex@attglobal.net> wrote in message
> news:6vCdnYaBloS7MZXZnZ2dnUVZ_vidnZ2d@comcast.com...
>
>>d wrote:
>>
>>>"Jerry Stuckle" <jstucklex@attglobal.net> wrote in message
>>>news:P4qdnZ1ghuZKFJXZRVn-qw@comcast.com...
>>>
>>>
>>>>fritz-bayer@web.de wrote:
>>>>
>>>>
>>>>>Hi,
>>>>>
>>>>>why does the php expression
>>>>>
>>>>>$result = 5543039447 & 2147483648;
>>>>>
>>>>>when executed evaluate to 0, whereas the perl expression
>>>>>
>>>>>$same = 5543039447 & 2147483648 ;
>>>>>
>>>>>evaluate to 2147483648 ???
>>>>>
>>>>>Fritz
>>>>>
>>>>
>>>>Because Perl is using 64 bit integers and PHP is using 32 bit integers.
>>>>
>>>>2147483648 is not a valid value in 32 bit arithmetic. The largest value
>>>>you can have is 2147483647.
>>>
>>>
>>>PHP interprets ints over 32 bits as floats, so they are valid.
>>>
>>>"If you specify a number beyond the bounds of the integer type, it will
>>>be interpreted as a float instead. Also, if you perform an operation that
>>>results in a number beyond the bounds of the integer type, a float will
>>>be returned instead."
>>>
>>>
>>>
>>>>--
>>>>==================
>>>>Remove the "x" from my email address
>>>>Jerry Stuckle
>>>>JDS Computer Training Corp.
>>>>jstucklex@attglobal.net
>>>>==================
>>>
>>>
>>>
>>In most cases, yes. However, you cannot perform bit operations on a
>>float. It must be an integer type.
>>
>>So the value is converted back to an integer, and since it's outside the
>>bounds of a 32 bit integer the result is to strip off the high order bits.
>>
>>The result is zero.
>
>
> The result is zero regardless of whether that bit is there or not :)
>
>
>>Sometimes a little knowledge is worse than no knowledge at all.
>>
>
>
> Indeed.
>
>
>>--
>>==================
>>Remove the "x" from my email address
>>Jerry Stuckle
>>JDS Computer Training Corp.
>>jstucklex@attglobal.net
>>==================
>
>
>
Actually, 0x80000000 is -2147483647 decimal. So the result is not zero.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================
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