I would like to change the behavior depending on the seller's user type in cart.php.
I think it can be implemented with code like this.
$user = User::newInstance()->findByPrimaryKey(osc_user_id());
if($user['b_company'] == 0 {

}
Thanks for your attention.

@HappyTiger
I would rather use:
osc_logged_user_id()
To get ID of user in cart.

Then, to be sure, on checking user type:
if(@$user['b_company'] != 1) {


@MB Themes
Thank you for your response.
I can get the user type of the user who is operating the cart page with your code, but how do I get the user type of the seller who created the ad?
$userId = User::newInstance()->findByPrimaryKey(osc_logged_user_id());
if(@$user['b_company'] != 0) {

}


@HappyTiger
$itemUser= User::newInstance()->findByPrimaryKey(osc_item_user_id());
if(@$itemUser['b_company'] != 1) {

}
... take more attention to naming of your variables, as well that in PHP 8, 0 != '', null != 0 (I think), so it's better to check against 1.

@MB Themes
Thanks for the advice.
I think I'm not fully understanding the article.

Nothing is displayed. $itemUser['b_company'] is empty.
$itemUser= User::newInstance()->findByPrimaryKey(osc_item_user_id());
echo $itemUser['b_company'];

Any user type react.
$itemUser= User::newInstance()->findByPrimaryKey(osc_item_user_id());
if(@$itemUser['b_company'] != 1) { }


@HappyTiger
osc_item_user_id() must be used on places, where this function does something (inside item loops, on item page etc).
Using it on random place will most probably not work.

@MB Themes
This problem was solved thanks to your support.

item-sidebar.php
session_start();
$itemUser = User::newInstance()->findByPrimaryKey(osc_item_user_id());
$_SESSION['itemUser'] = $itemUser['b_company'];
cart.php
if(@$_SESSION['itemUser'] != 1) { }