PHP interprets numbers as floats even when they're less than INT_MAX












0















PHP documentation here states that:




If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead. Also, an operation which results in a number beyond the bounds of the integer type will return a float instead.




But what about an operation which results in a number less than PHP_INT_MAX ?



See this code snippet as an example:



$max_int = 2**31-1 ; //  2147483647

var_dump(PHP_INT_MAX === $max_int); // false


As you can see, even when an operation results in a valid int value PHP seems to cast the result into float



var_dump(PHP_INT_MAX === (int) $max_int) // true


My questions:



Does PHP interpreter cast the result into float before making any calculations?



Shouldn't PHP calculate the result and then sets the type accordingly? (Makes sense right?)



Edit:



PHP version: 7.2.1 32-bit



OS: Windows: 10 x64



I'm using XAMPP






php integer-overflow







share|improve this question

























  • Do you know is the value of PHP_INT_MAX?

    – Pablo
    Nov 25 '18 at 22:05











  • @FatalError, I'm not sure that it happens like that for lesser integers. Please have a look here: 3v4l.org/S9hmd Could you also provide more info about the environment (os, PHP version) where this was happening?

    – Dan D.
    Nov 25 '18 at 22:15











  • Please see the edit

    – FatalError
    Nov 25 '18 at 22:27
















0















PHP documentation here states that:




If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead. Also, an operation which results in a number beyond the bounds of the integer type will return a float instead.




But what about an operation which results in a number less than PHP_INT_MAX ?



See this code snippet as an example:



$max_int = 2**31-1 ; //  2147483647

var_dump(PHP_INT_MAX === $max_int); // false


As you can see, even when an operation results in a valid int value PHP seems to cast the result into float



var_dump(PHP_INT_MAX === (int) $max_int) // true


My questions:



Does PHP interpreter cast the result into float before making any calculations?



Shouldn't PHP calculate the result and then sets the type accordingly? (Makes sense right?)



Edit:



PHP version: 7.2.1 32-bit



OS: Windows: 10 x64



I'm using XAMPP






php integer-overflow







share|improve this question

























  • Do you know is the value of PHP_INT_MAX?

    – Pablo
    Nov 25 '18 at 22:05











  • @FatalError, I'm not sure that it happens like that for lesser integers. Please have a look here: 3v4l.org/S9hmd Could you also provide more info about the environment (os, PHP version) where this was happening?

    – Dan D.
    Nov 25 '18 at 22:15











  • Please see the edit

    – FatalError
    Nov 25 '18 at 22:27














0












0








0








PHP documentation here states that:




If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead. Also, an operation which results in a number beyond the bounds of the integer type will return a float instead.




But what about an operation which results in a number less than PHP_INT_MAX ?



See this code snippet as an example:



$max_int = 2**31-1 ; //  2147483647

var_dump(PHP_INT_MAX === $max_int); // false


As you can see, even when an operation results in a valid int value PHP seems to cast the result into float



var_dump(PHP_INT_MAX === (int) $max_int) // true


My questions:



Does PHP interpreter cast the result into float before making any calculations?



Shouldn't PHP calculate the result and then sets the type accordingly? (Makes sense right?)



Edit:



PHP version: 7.2.1 32-bit



OS: Windows: 10 x64



I'm using XAMPP






php integer-overflow







share|improve this question
















PHP documentation here states that:




If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead. Also, an operation which results in a number beyond the bounds of the integer type will return a float instead.




But what about an operation which results in a number less than PHP_INT_MAX ?



See this code snippet as an example:



$max_int = 2**31-1 ; //  2147483647

var_dump(PHP_INT_MAX === $max_int); // false


As you can see, even when an operation results in a valid int value PHP seems to cast the result into float



var_dump(PHP_INT_MAX === (int) $max_int) // true


My questions:



Does PHP interpreter cast the result into float before making any calculations?



Shouldn't PHP calculate the result and then sets the type accordingly? (Makes sense right?)



Edit:



PHP version: 7.2.1 32-bit



OS: Windows: 10 x64



I'm using XAMPP






php integer-overflow




php integer-overflow






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 25 '18 at 22:26







FatalError

















asked Nov 25 '18 at 21:36









FatalErrorFatalError

4131311




4131311













  • Do you know is the value of PHP_INT_MAX?

    – Pablo
    Nov 25 '18 at 22:05











  • @FatalError, I'm not sure that it happens like that for lesser integers. Please have a look here: 3v4l.org/S9hmd Could you also provide more info about the environment (os, PHP version) where this was happening?

    – Dan D.
    Nov 25 '18 at 22:15











  • Please see the edit

    – FatalError
    Nov 25 '18 at 22:27



















  • Do you know is the value of PHP_INT_MAX?

    – Pablo
    Nov 25 '18 at 22:05











  • @FatalError, I'm not sure that it happens like that for lesser integers. Please have a look here: 3v4l.org/S9hmd Could you also provide more info about the environment (os, PHP version) where this was happening?

    – Dan D.
    Nov 25 '18 at 22:15











  • Please see the edit

    – FatalError
    Nov 25 '18 at 22:27

















Do you know is the value of PHP_INT_MAX?

– Pablo
Nov 25 '18 at 22:05





Do you know is the value of PHP_INT_MAX?

– Pablo
Nov 25 '18 at 22:05













@FatalError, I'm not sure that it happens like that for lesser integers. Please have a look here: 3v4l.org/S9hmd Could you also provide more info about the environment (os, PHP version) where this was happening?

– Dan D.
Nov 25 '18 at 22:15





@FatalError, I'm not sure that it happens like that for lesser integers. Please have a look here: 3v4l.org/S9hmd Could you also provide more info about the environment (os, PHP version) where this was happening?

– Dan D.
Nov 25 '18 at 22:15













Please see the edit

– FatalError
Nov 25 '18 at 22:27





Please see the edit

– FatalError
Nov 25 '18 at 22:27












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When calculating $max_int = 2**31-1 the engine does this in steps:



$tmp = 2**31;

$max_int = $tmp-1


Here $tmp is bigger than maximum integer value and converted to a floatng point number. In consequence there is an float subtraction, resulting in a float. Since it had been float it has to stay float.






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    3














    When calculating $max_int = 2**31-1 the engine does this in steps:



    $tmp = 2**31;
    
$max_int = $tmp-1


    Here $tmp is bigger than maximum integer value and converted to a floatng point number. In consequence there is an float subtraction, resulting in a float. Since it had been float it has to stay float.






    share|improve this answer




























      3














      When calculating $max_int = 2**31-1 the engine does this in steps:



      $tmp = 2**31;
      
$max_int = $tmp-1


      Here $tmp is bigger than maximum integer value and converted to a floatng point number. In consequence there is an float subtraction, resulting in a float. Since it had been float it has to stay float.






      share|improve this answer


























        3












        3








        3







        When calculating $max_int = 2**31-1 the engine does this in steps:



        $tmp = 2**31;
        
$max_int = $tmp-1


        Here $tmp is bigger than maximum integer value and converted to a floatng point number. In consequence there is an float subtraction, resulting in a float. Since it had been float it has to stay float.






        share|improve this answer













        When calculating $max_int = 2**31-1 the engine does this in steps:



        $tmp = 2**31;
        
$max_int = $tmp-1


        Here $tmp is bigger than maximum integer value and converted to a floatng point number. In consequence there is an float subtraction, resulting in a float. Since it had been float it has to stay float.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 25 '18 at 22:28









        johannesjohannes

        13k13355




        13k13355






























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