(PHP 4, PHP 5, PHP 7)
putenv — Sets the value of an environment variable
$setting
) : bool
Adds setting to the server environment. The
environment variable will only exist for the duration of the current
request. At the end of the request the environment is restored to its
original state.
Setting certain environment variables may be a potential security breach.
The safe_mode_allowed_env_vars directive contains a
comma-delimited list of prefixes. In Safe Mode, the user may only alter
environment variables whose names begin with the prefixes supplied by
this directive. By default, users will only be able to set environment
variables that begin with PHP_ (e.g.
PHP_FOO=BAR). Note: if this directive is empty, PHP
will let the user modify ANY environment variable!
The safe_mode_protected_env_vars directive contains a
comma-delimited list of environment variables, that the end user won't be
able to change using putenv(). These variables will
be protected even if safe_mode_allowed_env_vars is set
to allow to change them.
setting
The setting, like "FOO=BAR"
Returns TRUE on success or FALSE on failure.
Example #1 Setting an environment variable
<?php
putenv("UNIQID=$uniqid");
?>
The safe_mode_allowed_env_vars and
safe_mode_protected_env_vars directives only take
effect when safe_mode is
enabled.