What is the function of usleep in PHP?

In PHP, the usleep() function is used to pause the execution of a script for a certain amount of time, measured in microseconds. It can be used to implement delays or control the speed of code execution.

The syntax of this function is as follows:

void usleep ( int $micro_seconds )

In the parameter $micro_seconds, it represents the number of microseconds that need to be paused. One second equals 1000000 microseconds.

Here is an example usage of the usleep() function:

echo "Start\n";
usleep(500000); // 暂停0.5秒
echo "End\n";

The above code will output the following results:

Start
[等待0.5秒]
End

By using the usleep() function, you can control the speed at which your code executes, such as creating a delay within a loop to prevent excessive load on the server.