Check whether a session is started in PHP

this line will check if a session has started, if not, start it:

session_id() or session_start();

another alternative:

if(!session_id())
{
session_start();
}

Long time no see~

havn't been here for a while, master study is really stressful.
anyway, got some good news too, 3 of the baby guppies grew up already and ready to meet their new owner, I am going to deliver them tomorrow morning, hope they will enjoy their new home! One thing I am sure is that they will get much more sunshine overthere.
Time for bed, night all~