getenv()

getenv() — Gets the value of a single or all environment variables.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

Signature

getenv(?string $name = null, bool $local_only = false): string|array|false

Parameters

ParameterTypeWhat it takes
$name?stringThe variable name as a string or null.
$local_onlyboolWhen set to true, only local environment variables are returned, set by the operating system or putenv. It only has an effect when name is a string.

Return value

Returns the value of the environment variable name, or false if the environment variable name does not exist. If name is null, all environment variables are returned as an associative array.

Example

A runnable snippet:

// Example use of getenv() $ip = getenv('REMOTE_ADDR'); // Or simply use a Superglobal ($_SERVER or $_ENV) $ip = $_SERVER['REMOTE_ADDR']; // Safely get the value of an environment variable, ignoring whether // or not it was set by a SAPI or has been changed with putenv $ip = getenv('REMOTE_ADDR', true) ?: getenv('REMOTE_ADDR')

Changelog

VersionChange
8.0.0The name is now nullable.
7.1.0The name can now be omitted to retrieve an associative array of all environment variables.
7.0.9The local_only parameter has been added.

See also

putenv()

All PHP 8.5 built-in functions

Reference card built from the PHP manual page getenv() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.