Attempts to load a PHP extension at runtime when dynamic loading is allowed.
What Is dl() in PHP?
Attempts to load a PHP extension at runtime when dynamic loading is allowed.
Its syntax is:
dl(string $extension_filename): boolParameters:
$extension_filename— Accepted as string; required argument.
Return type: bool. Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input.
Availability: Requires enable_dl and a supported PHP SAPI; normally disabled on production websites.
Example 1: Basic Usage
<?php
echo function_exists("dl") ? "Loader exists" : "Unavailable";
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input.
Example 2: A Different Input
<?php
echo ini_get("enable_dl") ? "Dynamic loading enabled" : "Dynamic loading disabled";
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input.
Practical Example: Applying It in a Program
<?php
if (!extension_loaded("intl")) { echo "Install or enable intl in the server configuration rather than loading it per request."; }
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input.
Important Behavior and Edge Cases
- Key behavior: Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input.
- Environment: Requires enable_dl and a supported PHP SAPI; normally disabled on production websites.
Comparison With Related Functions
| Function | Purpose |
|---|---|
dl() | Attempts to load a PHP extension at runtime when dynamic loading is allowed. |
extension_loaded() | extension_loaded() only checks current availability; dl() attempts runtime loading where PHP permits it. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Ignoring this behavior: Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input | Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input. |
Key Takeaways
- Attempts to load a PHP extension at runtime when dynamic loading is allowed.
- Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input.
- Requires enable_dl and a supported PHP SAPI; normally disabled on production websites.
Summary: Dynamic loading is commonly disabled in web SAPIs; do not attempt to load arbitrary extension paths from user input.