Use var_dump to debug time_nanosleep to return value instance

In PHP development, time_nanosleep is a function for implementing nanosecond-level delays, which is very practical for scenarios where precise control of script execution time is required. However, the return value of the function can be confusing to beginners, especially when debugging is not very clear what it actually returns. This article will help you understand and debug the return value of time_nanosleep through the use of var_dump .

1. Introduction to time_nanosleep function

 bool|array time_nanosleep(int $seconds, int $nanoseconds)

time_nanosleep accepts two parameters:

• $seconds : The number of seconds to wait.

• $nanoseconds : The number of extra nanoseconds to wait (1 second = 1,000,000,000 nanoseconds).

Return value:

• Returns true on success.

• If interrupted by a signal, an array is returned, containing seconds and nanoseconds representing the remaining time at the interruption.

2. Use var_dump to view the return value

var_dump is a very practical debugging tool in PHP. It can output the types and values ​​of variables in full, which is very suitable for viewing the return structure of time_nanosleep .

Example 1: Wait normally

 <?php
$result = time_nanosleep(1, 500000000); // wait 1.5 Second
var_dump($result);

Output:

 bool(true)

It means that the script has been successfully paused for 1.5 seconds and completed normally.

Example 2: Human interrupt (simulation)

To simulate interrupt effects, we can implement them through signal processing or call environments, but it is difficult to implement them directly under regular CLI. To demonstrate the return structure, we manually construct the following:

 <?php
// Assume it is interrupted
$interrupted_result = [
    'seconds' => 0,
    'nanoseconds' => 200000000,
];
var_dump($interrupted_result);

Output:

 array(2) {
  ["seconds"]=>
  int(0)
  ["nanoseconds"]=>
  int(200000000)
}

This is the return value structure when time_nanosleep is interrupted.

3. Comprehensive example: Encapsulation check function

We can encapsulate a function to use time_nanosleep and debug its return value using var_dump :

 <?php
function preciseSleep(int $sec, int $nano) {
    echo "Sleeping for {$sec} seconds and {$nano} nanoseconds...\n";
    $result = time_nanosleep($sec, $nano);
    echo "Result of time_nanosleep:\n";
    var_dump($result);
    
    if (is_array($result)) {
        echo "Sleep was interrupted. Remaining time:\n";
        echo "Seconds left: " . $result['seconds'] . "\n";
        echo "Nanoseconds left: " . $result['nanoseconds'] . "\n";
    } elseif ($result === true) {
        echo "Sleep completed successfully.\n";
    } else {
        echo "Unknown return value.\n";
    }
}

preciseSleep(2, 0);

When running the script, you can observe the detailed structure of the var_dump output, thereby helping you further debug the behavior of the program.

4. Debugging suggestions

1. Always use with var_dump : When using time_nanosleep , whether you expect interrupts or not, you should use var_dump to observe its return value.

2. Use logging : Do not var_dump directly to the screen in production environment. It is recommended to write debug information to the log file:

    file_put_contents('/var/log/nano_debug.log', print_r($result, true));
   

3. Pay attention to system interrupts : If your script receives a signal (such as SIGINT ), it will cause a time_nanosleep interrupt, and this situation needs to be handled specifically.

5. Examples of application scenarios

When connecting to the API, you may use time_nanosleep to achieve throttling, for example:

 <?php
// Simulate each request interval 1 Second
for ($i = 0; $i < 3; $i++) {
    file_get_contents("https://gitbox.net/api/data/{$i}");
    time_nanosleep(1, 0);
}

With var_dump , you can ensure that script execution is expected to be executed, especially in debugging load balancing or rate limiting scenarios.