Commonly used constants in PHP
A quick reference of commonly used PHP core constants (EOL markers, integer limits, float ranges) and why they matter for portable code.
These constants are defined by the PHP core.
| Constant | Description |
|---|---|
| PHP_EOL | The correct ‘End Of Line’ symbol for this platform. Available since PHP 5.0.2 |
| PHP_INT_MAX | The largest integer supported in this build of PHP. Usually int(2147483647) in 32 bit systems and int(9223372036854775807) in 64 bit systems. Available since PHP 5.0.5 |
| PHP_INT_MIN | The smallest integer supported in this build of PHP. Usually int(-2147483648) in 32 bit systems and int(-9223372036854775808) in 64 bit systems. Available since PHP 7.0.0. Usually, PHP_INT_MIN === ~PHP_INT_MAX. |
| PHP_INT_SIZE | The size of an integer in bytes in this build of PHP. Available since PHP 5.0.5 |
| PHP_FLOAT_EPSILON | Smallest representable positive number x, so that x + 1.0 != 1.0. Available as of PHP 7.2.0. |
| PHP_FLOAT_MIN | Smallest representable floating point number. Available as of PHP 7.2.0. |
| PHP_FLOAT_MAX | Largest representable floating point number. Available as of PHP 7.2.0. |
Note
It is better to use PHP_EOL when you need to put new line characters. Since the difference between new line characters in different systems, PHP_EOL can improve the portability of your codes to some extent.