190a392d_th_PHP___Page_2___WebReference__Flags
[Filter] FILTER_VALIDATE_INT [Options] min_range max_range [Description] Checks for an integer; returns false for any other data type. Specify the minimum and maximum acceptable values as an associative array using min_range and max_range (you can set just one or both together). Flags permit octal and hexadecimal numbers. Rejects numbers with a decimal point, even if the fraction is 0, for example, 10.0. [Flags] 
FILTER_FLAG_ALLOW_OCTAL FILTER_FLAG_ALLOW_HEX
Data Filtering with PHP / Page 2 | WebReference
Flags