The 'return' keyword is not working correctly in PHP

Question

I am using this piece of function to check if a file exists. If the file exists then I am changing its name:

function checkFileExist($fileName, $z, $ext, $folderWIthFileName){
    $tmpNam = "";
    if (file_exists($fileName . "_" . $z . "." . $ext)) {
        $z = $z + 1;
        checkFileExist($fileName, $z, $ext, $folderWIthFileName);
    }
    else {
        $tmpNam = $fileName . "_" . $z;
        echo "in else <br> " . $fileName . "_" . $z . "<br>";
    }
    return $tmpNam;
}

And calling this function like

$definename = checkFileExist($folderWIthFileName . "/" . $InvId, $z, $ext, $folderWIthFileName);
echo "new name is " . $definename;

But this gives me output like this:

in else
444_2015-10-27/444_3
new name is

You can see return is not working correctly. What am I doing wrong here?

Answer 1

You should use return checkFileExist($fileName, $z, $ext, $folderWIthFileName); in the first block to return back a value from the recursively made calls. Use this clean version:

function checkFileExist($fileName, $z, $ext, $folderWIthFileName) {
    if (file_exists($fileName . "_" . $z . "." . $ext)) {
        return checkFileExist($fileName, $z+1, $ext, $folderWIthFileName);
    }
    return $fileName . "_" . $z;
}