Returns a string containing a hexadecimal representation of the given unsigned num argument.
The largest number that can be converted is PHP_INT_MAX * 2 + 1 (or -1): on 32-bit platforms, this will be 4294967295 in decimal, which results in dechex returning ffffffff.
The decimal value to convert.
As PHP's int type is signed, but dechex deals with unsigned integers, negative integers will be treated as though they were unsigned.
Hexadecimal string representation of num.