PHP Long integer forced conversion overflow in 32-bit system

Clevercode recently encountered a PHP project shaping transformation problem, MySQL has a field ID is bigint, there is a long integer, such as id = 5147486396. However, the PHP code is deployed in several machines for historical reasons, including a machine 32-bit system, B machine 64 system. The problem now is that page access is normal in the 64 system. There was an error accessing the 32-bit system. The reason is that PHP shaping overflows.

1 A machine demo 1.1 get a machine system number of bits

# getconf Long_bit

1.2 Shaping the conversion code

<?php$id = 5147486396;echo ' $id: '. $id. ' \ r \ n "; $value = (int) $id; echo ' (int) $id: '. $value." \ r \ n "; $value = Intval ($id); Echo ' Intval ($id): '. $value." \ r \ n "; $value = Filter_var ($id, filter_validate_int); Echo ' Filter_var ($id, Filter_validate_int): '. ' \ r \ n "; var_dump ($value);? >

1.3 Result of the run result (int) 5147486396 is the result of 852519100,intval (5147486396) is 852519100,filter_var (5147486396, Filter_validate_int) The result is false.



2 B Machine Demo 2.1 Get B machine system number of bits # getconf Long_bit

2.2 Shaping the conversion code

<?php$id = 5147486396;echo ' $id: '. $id. ' \ r \ n "; $value = (int) $id; echo ' (int) $id: '. $value." \ r \ n "; $value = Intval ($id); Echo ' Intval ($id): '. $value." \ r \ n "; $value = Filter_var ($id, filter_validate_int); Echo ' Filter_var ($id, Filter_validate_int): '. ' \ r \ n "; var_dump ($value);? >

The result of 2.3 running result (int) 5147486396 is that the result of 5147486396,intval (5147486396) is 5147486396,filter_var (5147486396, Filter_validate_ INT) The result is 5147486396.

3 conclusion The word length of the integer number is related to the platform, although the usual maximum value is approximately 2 billion (32-bit signed). The maximum value under a 64-bit platform is usually approximately 9E18. PHP does not support unsigned integers. The length of the Integer value can be expressed as a constant php_int_size, since PHP 4.4.0 and PHP 5.0.5, the maximum value can be expressed as a constant php_int_max.


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PHP Long integer forced conversion overflow in 32-bit system