致命错误：第15行的C：\ xampp \ htdocs \ main.php中允许的内存大小为134217728字节（试图分配8192字节）

Question

I have Problem with my recursion function. I want to wait until text file input change then redirect to new page.

15 line is

$readedData = fread($myfile,filesize("my1.txt"));

this is my function

first();

function first() {
    $myfile = fopen("my1.txt", "r") or die("Unable to open file!");
    $number = fread($myfile,filesize("my1.txt"));

    fclose($myfile);
    recursion($number);
}

function recursion($number2) { 
    $myfile = fopen("my1.txt", "r") or die("Unable to open file!");
    $readedData = fread($myfile,filesize("my1.txt"));

    echo ($readedData ); 

    fclose($myfile);
    if($number2 != $readedData){
        return (recursion($readedData));
    }
    else if($number2 == $readedData){
        return(first());
    }
}

Answer 1

Yes you do, your recursion is not bounded, it keeps calling deeper and deeper. Waiting for a condition is usually handled with a conditional loop, not self-recursion.

first() always calls recursion()

recursion() calls itself, or calls first(). Which always calls recursion().

You see the problem -- these calls never end, they always call recursion(). Each call allocates stack space to be able to run, until the maximum configured limit is hit (130MB by default, which is what your error reported too)

Edit: php has no setInterval() like javascript, and in php recursive calls are truly recursive, they do not just queue a continuable. To wait until the file changes in a loop you can do something like:

function waitAndRedirect( $filename ) {
    waitForchange(file_get_contents($filename));
    handleRedirect();
}

function waitForChange( $oldData ) {
    while (true) {
        $currentData = file_get_contents($filename);
        if ($currentData !== $oldData) return;
        else usleep(200);
    }
}