PHP: Predefined Constants - Manual - PHP: Hypertext Preprocessor
Another way to determine PHP_INT_MIN: It should work always: MAX for 8bit-signed: 01111111 MIN for 8bit-signed: 10000000 In 32 bits: php -r"echo (int)base_convert(str_repeat('1', 31), 2, 10) - PHP_INT_MAX;" 0 ......