php sets the maximum running time of a function

How to prevent a function from taking too long to execute? In PHP, you can use pcntl clock signal + exception to achieve

declare(ticks = 1);
function a()
{
    sleep(10);
    echo "a finishi\n";
}
function b()
{
    echo "Stop\n";
}
function c()
{
    usleep(100000);
}
 
function sig()
{
    throw new Exception;
}
 
try
{
    pcntl_alarm(1);
    pcntl_signal(SIGALRM, "sig");
    a();
    pcntl_alarm(0);
}
catch(Exception $e)
{
    echo "timeout\n";
}
 
b();
a();
b();

The principle is to set a clock signal before the function is executed. If the execution of the function exceeds the specified time, the signal will be triggered, and the signal processing function will throw an exception. Caught by outer code. This will jump out of the execution of the original function, and then execute the following code. If the function is within the specified time, the clock signal will not be triggered. The clock signal will be cleared after the function ends, and no exception will be thrown.