PHP interprets numbers as floats even when they're less than INT_MAX
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
asked Nov 25 '18 at 21:36
FatalErrorFatalError
4131311
add a comment |
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
asked Nov 25 '18 at 21:36
FatalErrorFatalError
4131311
Do you know is the value ofPHP_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
add a comment |
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
asked Nov 25 '18 at 21:36
FatalErrorFatalError
4131311
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
asked Nov 25 '18 at 21:36
FatalErrorFatalError
4131311
asked Nov 25 '18 at 21:36
FatalErrorFatalError
4131311
edited Nov 25 '18 at 22:26
FatalError
asked Nov 25 '18 at 21:36
FatalErrorFatalError
4131311
asked Nov 25 '18 at 21:36
FatalErrorFatalError
4131311
asked Nov 25 '18 at 21:36
FatalErrorFatalError
4131311
4131311
Do you know is the value ofPHP_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
add a comment |
Do you know is the value ofPHP_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
add a comment |
1 Answer
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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.
answered Nov 25 '18 at 22:28
johannesjohannes
13k13355
add a comment |
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1 Answer
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1 Answer
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active
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oldest
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votes
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.
answered Nov 25 '18 at 22:28
johannesjohannes
13k13355
add a comment |
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.
answered Nov 25 '18 at 22:28
johannesjohannes
13k13355
add a comment |
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.
answered Nov 25 '18 at 22:28
johannesjohannes
13k13355
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.
answered Nov 25 '18 at 22:28
johannesjohannes
13k13355
answered Nov 25 '18 at 22:28
johannesjohannes
13k13355
answered Nov 25 '18 at 22:28
johannesjohannes
13k13355
answered Nov 25 '18 at 22:28
johannesjohannes
13k13355
13k13355
add a comment |
add a comment |
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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