PHP get_resource_id() Function: Usage and Examples

Use get_resource_id() when you need to returns the numeric identifier of a resource value in a PHP application. The examples below show the actual operation and its limitations.

What Is get_resource_id() in PHP?

Returns the numeric identifier of a resource value. The exact signature supported by your installation depends on its PHP version and enabled extensions.

Its syntax is:

get_resource_id($resource): int

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

$stream = fopen("php://temp","w+"); echo get_resource_id($stream); fclose($stream);

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

$stream = fopen("php://temp","w+"); var_dump(is_int(get_resource_id($stream))); fclose($stream);

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

$stream = fopen("php://temp","w+"); echo "Stream #" . get_resource_id($stream); fclose($stream);

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

Resource IDs may be reused and are not stable identifiers across requests.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Returns the numeric identifier of a resource value.
• Resource IDs may be reused and are not stable identifiers across requests.
• get_resource_type() reports the resource category rather than its integer ID.

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