Doc #63027 [Opn->Csd]: dechex may convert numbers up to PHP_INT_MAX

Edit report at https://bugs.php.net/bug.php?id=63027&edit=1 ID: 63027 Updated by: aharvey@php.net Reported by: marc at ermshaus dot org Summary: dechex may convert numbers up to PHP_INT_MAX -Status: Open +Status: Closed Type: Documentation Problem Package: Documentation problem Operating System: 64-bit PHP Version: Irrelevant -Assigned To: +Assigned To: aharvey Block user comment: N Private report: N New Comment: This bug has been fixed in the documentation's XML sources. Since the online and downloadable versions of the documentation need some time to get updated, we would like to ask you to be a bit patient. Thank you for the report, and for helping us make our documentation better. Previous Comments: ------------------------------------------------------------------------ [2012-09-10 01:54:04] aharvey@php.net Automatic comment from SVN on behalf of aharvey Revision: http://svn.php.net/viewvc/?view=revision&revision=327571 Log: Fix doc bug #63027 (dechex may convert numbers up to PHP_INT_MAX) by clarifying that PHP treats the parameter as an unsigned int, and working through some of the implications of that from a userland perspective. ------------------------------------------------------------------------ [2012-09-07 09:44:02] marc at ermshaus dot org “[…] as PHP uses unsigned longs.” Sorry, that should be *signed* longs. ------------------------------------------------------------------------ [2012-09-07 08:53:11] marc at ermshaus dot org Description: ------------ The range of this function seems to be platform dependent and contain the whole range of the C long type. The documentation states: “Returns a string containing a hexadecimal representation of the given number argument. The largest number that can be converted is 4294967295 in decimal resulting to "ffffffff".” Technically, that would be the interval [-PHP_INT_MAX - 1, PHP_INT_MAX] as PHP uses unsigned longs. Implementation details: - dechex: https://github.com/php/php-src/blob/b47d6b32ba8d6dc1b9d1fc91a83eef29a28363c5/ext/standard/math.c#L1047 Calls: - convert_to_long_ex: https://github.com/php/php-src/blob/b47d6b32ba8d6dc1b9d1fc91a83eef29a28363c5/Zend/zend_operators.h#L398 - convert_to_ex_master: https://github.com/php/php-src/blob/b47d6b32ba8d6dc1b9d1fc91a83eef29a28363c5/Zend/zend_operators.h#L355 - convert_to_long: https://github.com/php/php-src/blob/b47d6b32ba8d6dc1b9d1fc91a83eef29a28363c5/Zend/zend_operators.c#L324 - convert_to_long_base: https://github.com/php/php-src/blob/b47d6b32ba8d6dc1b9d1fc91a83eef29a28363c5/Zend/zend_operators.c#L332 Then strtol from stdlib would be called which returns a long. Test script: --------------- var_dump( PHP_INT_SIZE, PHP_INT_MAX, dechex(PHP_INT_MAX), dechex(-PHP_INT_MAX - 1), dechex(-1) ); int(8) int(9223372036854775807) string(16) "7fffffffffffffff" string(16) "8000000000000000" string(16) "ffffffffffffffff" ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=63027&edit=1