CanUserAddSubscribe

bool
CanUserAddSubscribe(
 int FID,
 array arUserGroups
);

Thoroughly checks whether a user of a specified group can subscribe to the specified forum.

Parameter	Description
FID	The ID of the forum to which (whole or thread) a user wants to subscribe.
arUserGroups	Array of groups that the user is member of. For the current user, you can obtain this array by calling `$USER->GetUserGroupArray()`.

Returns true is the user can subscribe, or false otherwise.