PHP get_defined_vars() Function: Usage and Examples

Use get_defined_vars() when you need to returns variables visible in the current scope in a PHP application. The examples below show the actual operation and its limitations.

What Is get_defined_vars() in PHP?

Returns variables visible in the current scope. The exact signature supported by your installation depends on its PHP version and enabled extensions.

Its syntax is:

get_defined_vars(): array

Parameters and return value: The parameter types, optional arguments, references, and return type are shown in the signature above. Optional parameters are marked with an ellipsis in this reference signature.

Example 1: Basic Usage

<?php

function scopeExample() { $username = "Alex"; return array_keys(get_defined_vars()); } print_r(scopeExample());

Result: Run the example in an environment that supports the function. Any values depending on operating-system state, installed extensions, process configuration, or network access must be checked on the target server.

Example 2: Different Input or Behavior

<?php

function localsExample() { $count = 2; return get_defined_vars()["count"]; } echo localsExample();

Result: Run the example in an environment that supports the function. Any values depending on operating-system state, installed extensions, process configuration, or network access must be checked on the target server.

Practical Example: Applying the Function

<?php

function debugOrder($orderId, $total) { $vars = get_defined_vars(); return isset($vars["orderId"],$vars["total"]); } var_dump(debugOrder(5, 20));

Result: Run the example in an environment that supports the function. Any values depending on operating-system state, installed extensions, process configuration, or network access must be checked on the target server.

Important Behavior and Edge Cases

Never dump all variables in production: they may include secrets or personally identifiable data.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Returns variables visible in the current scope.
• Never dump all variables in production: they may include secrets or personally identifiable data.
• compact() selects named variables; get_defined_vars() returns all visible variables.

Use get_defined_vars() for the specific operation demonstrated above. Check its prerequisites and handle failure conditions before using it with production data.