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(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.