Ben Kodigniter index.php aşağıdaki kodu var

Benim anlayış olduğunu,

If / of string position in $system_folder (in this case CIcore_1_7_1) is false, and if realpath function exists AND (I don't understand here) is not false, $system_folder is assigned to (I don't understand here) /$system_folder. else $system_folder is assigned to $system_folder with replacing \ with /.

Q1. Ne realpath fonksiyon ne demek?

Q2. Bu ne anlama geliyor?

@realpath(dirname(__FILE__))

Q3. Haklı mıyım? Ben herhangi bir yanlış anlama var mı?

Q4. Durumun ne tür aşağıdaki gerekiyor?

str_replace("\\", "/", $system_folder)

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Kod

$system_folder = "CIcore_1_7_1";

/*
|---------------------------------------------------------------
| SET THE SERVER PATH
|---------------------------------------------------------------
|
| Let's attempt to determine the full-server path to the "system"
| folder in order to reduce the possibility of path problems.
| Note: We only attempt this if the user hasn't specified a 
| full server path.
|
*/
if (strpos($system_folder, '/') === FALSE)
{
    if (function_exists('realpath') AND @realpath(dirname(__FILE__)) !== FALSE)
    {
    	$system_folder = realpath(dirname(__FILE__)).'/'.$system_folder;
    }
}
else
{
    // Swap directory separators to Unix style for consistency
    $system_folder = str_replace("\\", "/", $system_folder); 
}