(PHP 4, PHP 5, PHP 7, PHP 8)
getenv — Gets the value of a single or all environment variables
Gets the value of a single or all environment variables.
You can see a list of all the environmental variables by using phpinfo(). Many of these variables are listed within » RFC 3875, specifically section 4.1, "Request Meta-Variables".
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.
| Version | Description |
|---|---|
| 8.0.0 |
The name is now nullable.
|
| 7.1.0 |
The name can now be omitted to retrieve an
associative array of all environment variables.
|
| 7.0.9 |
The local_only parameter has been added.
|
Example #1 getenv() Example
<?php
// 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')
?>
If PHP is running in a SAPI such as Fast CGI, this function will
always return the value of an environment variable set by the SAPI,
even if putenv() has been used to set a local
environment variable of the same name. Use the local_only
parameter to return the value of locally-set environment variables.