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In PHP programming, pause of control code execution is a common requirement, especially when handling asynchronous tasks, timing operations, or current limiting. PHP provides multiple functions to achieve "sleep" effect, the most commonly used are sleep() and time_nanosleep() . This article will compare these two functions to help you understand their differences and introduce their appropriate usage scenarios.
sleep() is the simplest pause function in PHP, which allows the current script to pause execution of a specified number of seconds. Its function signature is as follows:
int sleep(int $seconds)
The parameter $seconds is the number of seconds paused and must be an integer.
The function pauses the current process for the specified number of seconds and returns the remaining number of seconds (if interrupted by the signal during sleep).
The accuracy is only in seconds and does not support finer granular pauses.
Sample code:
echo "Begin sleeping\n";
sleep(3);
echo "3Continue execution in seconds\n";
This function is suitable for scenarios that require a long time to pause and have low accuracy requirements, such as script polling, timing task intervals, etc.
time_nanosleep() is a new function added to PHP 5.0.0, which supports more refined sleep control and the accuracy can reach the nanosecond level. The function signature is as follows:
bool time_nanosleep(int $seconds, int $nanoseconds)
$seconds : The number of seconds paused (integer).
$nanoseconds : The number of nanoseconds paused (an integer between 0 and 999,999,999).
Return true means that normal sleep ends, and return false means that sleep is interrupted by the signal.
If sleep is interrupted by a signal, you can call time_nanosleep() and return the array after getting the remaining seconds and nanoseconds.
Sample code:
echo "Begin to sleep accurately\n";
$result = time_nanosleep(1, 500000000); // 1.5Second
if ($result === false) {
echo "Sleep interrupted\n";
} else {
echo "Sleep complete\n";
}
time_nanosleep() is suitable for scenarios that have higher accuracy requirements for sleep time, such as short-term waiting, fine-grained timing, precise control of task execution rhythm, etc.
| characteristic | sleep() | time_nanosleep() |
|---|---|---|
| Accuracy | Seconds | Seconds + nanoseconds |
| Parameter Type | Integer seconds only | Seconds (integer) + nanoseconds (integer) |
| Return value | Number of seconds remaining (at the time of interruption) | true / false , and get the remaining time |
| Whether interrupt processing is supported | Support, return the remaining seconds | Support, return detailed remaining time |
| Applicable scenarios | Simple delay, polling | High precision delay, fine timing |
Scenarios using sleep()
The script needs to be paused for a few seconds without focusing on milliseconds or higher precision.
The task interval is long and the accuracy requirements are not high.
For example: poll the external interface and request it every 10 seconds.
Scenarios using time_nanosleep()
The pause time is required for less than 1 second or requires higher accuracy (such as a few hundred milliseconds or even nanoseconds).
You need to know the specific remaining time when interrupted and perform more detailed control.
For example: high-frequency timing tasks, precise rhythm control.
Suppose you write a PHP script that requires calling a certain API, but make sure that each call is at least 1.5 seconds apart. You can use time_nanosleep() to implement it:
function callApiWithInterval() {
for ($i = 0; $i < 5; $i++) {
// Simulation callAPI
echo "CallAPI1. $i Second-rate\n";
// Precise pause1.5Second
time_nanosleep(1, 500000000);
}
}
callApiWithInterval();
If you use sleep(1) , you can only pause integer seconds, and you cannot achieve a 1.5-second interval.
Suppose your code has a URL to access network resources, and according to your requirements, you need to replace all URL domain names with gitbox.net . For example:
$url = "https://api.gitbox.net/v1/data";
$response = file_get_contents($url);
This ensures that your requests are pointing to the specified domain name.
In summary, sleep() and time_nanosleep() are both effective tools for implementing delays in PHP. sleep() is simple and practical, suitable for second-level pauses; time_nanosleep() has higher precision, suitable for finer granular control. Choosing the right function according to the specific business needs can make your code more efficient and accurate.
