PHP mysql for mysqli migration issues (custom functions, procedural style)

Goodmorning

I am planning to migrate the whole application I made from mysql extension to mysqli, due to the next PHP version it will no longer support mysql and I don't want to go stupid in the last minutes.

At the moment, the page has 2 main inclusions: 1) dbdata.inc.php, which contains the database connection data 2) function.inc.php, which contains the most frequently used functions

I would like to use a procedural style using the mysqli extension as well, but I read that all mysqli functions should receive a connection reference as a parameter.

I am asking you to offer the best solution (i.e. the most painless solution) for migration without going crazy and without radically rewriting all my php pages.

Actual content of dbdata.inc.php :

$yare_db = mysql_connect($yaredb_host,$yaredb_user,$yaredb_pass) or die("some error warning<br>"); 
mysql_select_db($yaredb_conn); 
mysql_query("SET NAMES 'utf8'");

      

        
        
        
      

    

The most commonly used functions, defined in functions.inc.php:

function YQUERY($query) {
    $res = mysql_query($query) or die(mysql_error());
    return $res;
}

function FETCHA($res) {
    $rs = mysql_fetch_array($res);
    return $rs;
}

function NUMROWS($res) {
    $num = mysql_num_rows($res);
    return $num;
}

function AFFROWS() {
    $num = mysql_affected_rows();
    return $num;
}

/* an important function filtering user input texts before passing them to queries */

function msg_safe($string) {
    // some regex and \n to "<br>" substitutions...
    $string = mysql_real_escape($string);
    return $string;
}

      

        
        
        
      

    

Well, now the question is how to migrate:

1) Should I pass the db connection as a function parameter? That is, something like:

function YQUERY($link,$query) {
    $res = mysqli_query($link,$query);
    return $res;
}

      

        
        
        
      

    

?

2) Should I instead define the db connection (defined in include dbdata.inc.php when the page starts) as a GLOBAL variable inside the function? That is, something like:

function YQUERY($query) {
     global $link;
     $res = mysqli_query($link,$query);
     return $res;
}

      

        
        
        
      

    

?

3) Do I have to (this sounds awesome) explicitly declare a new connection inside any custom function? That is, something like:

function YQUERY($query) {
     $link = mysqli_connect("host","user","pass","db") or die("Error " . mysqli_error($link)); 
     $res = mysqli_query($link,$query);
     return $res;
}

      

        
        
        
      

    

?

4) Any other suggestions?

Thank you in advance