What happens when the nanosecond parameter is out of range when using time_nanosleep?

gitbox 2025-05-27

According to the official documentation, the nanosecond parameter of time_nanosleep must be in the range of 0 to 999,999,999. What happens if the incoming nanosecond value exceeds this range?

1. Function call fails and returns false

When the nanosecond parameter exceeds 999,999,999 or less than 0, the time_nanosleep function will immediately return false , indicating that the function call failed. This means that the program will not hibernate for any time.

2. Generate PHP warning (Warning)

In some PHP versions, if an invalid nanosecond parameter is passed, a runtime warning is triggered, prompting that the parameter is out of range. This helps developers to detect parameter passing errors in time.

3. The program will not be paused as expected

Due to failure of function call, the program does not wait for the specified time, which may lead to subsequent logical execution order and timing exceptions, especially in scenarios that rely on precise timing.

Sample code

Here is an example that demonstrates how to perform when passing in nanosecond parameters that are out of range:

 <?php
// Nanosecond parameters are within normal range，Sleep1Half a second（1Second + 500,000,000纳Second）
var_dump(time_nanosleep(1, 500000000)); // Output bool(true)

// 纳Second参数超出范围，Exceeding maximum value
var_dump(time_nanosleep(1, 1000000000)); // Output bool(false)，And there may be warnings

// 纳Second参数负数
var_dump(time_nanosleep(1, -100)); // Output bool(false)，And there may be warnings
?>

Run the above code, if your PHP version supports it, you will see the second and third calls return false and prompt a warning message.

Handling suggestions

Ensure the legality of parameters <br> Before calling time_nanosleep , be sure to check the nanosecond parameter to make sure it is between 0 and 999,999,999. The exception parameters can be filtered using simple conditions.
Use try-catch or error handling mechanism <br> Combined with custom error handling or exception catching, catch potential warnings and avoid program crashes.
Reasonable split time parameters <br> If the sleep time is required for more than 1 second, you can split it into two parameters: seconds and nanoseconds to avoid the number of nanoseconds being out of range.

in conclusion

The time_nanosleep function requires strict legality of nanosecond parameters. When it is out of range, it will cause the function call to fail and return false , and may also trigger a warning. In order to ensure the stable operation of the program, it is necessary to verify the parameter range to avoid passing in illegal values.