Reports the CPU index on which the running process is executing, when supported by the operating system.
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 pcntl_getcpu() in PHP?
Reports the CPU index on which the running process is executing, when supported by the operating system.
Syntax:
<?php
// Signature for reference only
pcntl_getcpu() : int
Parameters and Return Value
This operation does not accept any arguments.
The declared return type is int.
Example 1: Basic Usage
<?php
// Linux and a compatible PHP version are required.
$currentCpu = pcntl_getcpu();
var_dump($currentCpu);Reports the CPU index on which the running process is executing, when supported by the operating system.
Example 2: Another Case
<?php
$currentCpu = pcntl_getcpu();
if ($currentCpu !== false) { echo "Running on CPU " . $currentCpu; }The second sample illustrates a different way to inspect or handle this operation. Configure the underlying session, socket, key material or connection first.
Practical Example
<?php
$currentCpu = pcntl_getcpu();
echo is_int($currentCpu) ? "CPU ID: " . $currentCpu : "CPU unavailable";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
- Availability and permission rules differ by host; never give web requests unrestricted process-control privileges.
- Relevant PHP environment: pcntl. 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 |
|---|---|
pcntl_getcpu | Reports the CPU index on which the running process is executing, when supported by the operating system. |
posix_getpid | 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 the CPU index on which the running process is executing, when supported by the operating system.
- Availability and permission rules differ by host; never give web requests unrestricted process-control privileges.
- Validate inputs and handle failure conditions before integrating this operation into a production workflow.
Reports the CPU index on which the running process is executing, when supported by the operating system. Use the appropriate runtime and treat any environment-dependent output as an example, not a guaranteed result.