Reports how many bytes PHP currently allocates through its memory manager, including optional allocated capacity.
Before using it, identify which data, connection or runtime state the operation reads or changes. This avoids examples that appear to work but apply to a different context.
What Is memory_get_usage() in PHP?
Reports how many bytes PHP currently allocates through its memory manager, including optional allocated capacity.
Syntax:
<?php
// Signature for reference only
memory_get_usage([optional] bool $real_usage) : int
Parameters and Return Value
$real_usage— Optional bool argument supplied to this operation.
The declared return type is int.
Example 1: Basic Usage
<?php
echo memory_get_usage(false);Reports how many bytes PHP currently allocates through its memory manager, including optional allocated capacity.
Example 2: Another Case
<?php
echo memory_get_usage(true);The second example changes the input or surrounding conditions, which matters when choosing this API for real application code.
Practical Example
<?php
$beforeBytes = memory_get_usage();
$sampleNumbers = range(1, 10000);
$afterBytes = memory_get_usage();
echo "Change: " . ($afterBytes - $beforeBytes) . " bytes";The practical example is a teaching scenario. Change sample configuration and credentials before using a similar design in an application.
Important Behavior and Edge Cases
- The result changes with allocation activity; it is not a complete measure of the PHP process RSS.
- Relevant PHP environment: standard. Ensure the required extension and operating-system capabilities are present.
- Check results and release resources where necessary; successful syntax alone does not guarantee a successful operation.
Comparison With Related Functions
| Option | When to Use It |
|---|---|
memory_get_usage | Reports how many bytes PHP currently allocates through its memory manager, including optional allocated capacity. |
memory_get_peak_usage | Use this related operation for its different responsibilities; do not assume identical inputs or return values. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Assuming a successful return value | Inspect the returned value and handle failures according to this operation’s contract. |
| Using the API without its required environment | Supply the required resources, runtime configuration and permissions before calling it. |
| Copying demonstration values into production | Use application-specific validated values, secure configuration and safe error handling. |
Key Takeaways
- Reports how many bytes PHP currently allocates through its memory manager, including optional allocated capacity.
- The result changes with allocation activity; it is not a complete measure of the PHP process RSS.
- Validate inputs and handle failure conditions before integrating this operation into a production workflow.
Reports how many bytes PHP currently allocates through its memory manager, including optional allocated capacity. Use the appropriate runtime and treat any environment-dependent output as an example, not a guaranteed result.