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Posted by Jerry Stuckle on 11/18/24 11:41
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.
Sometimes a little knowledge is worse than no knowledge at all.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================
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