The pam_open_session
function sets up a user session for a previously successful
authenticated user. The session should later be terminated
with a call to pam_close_session(3).
It should be noted that the effective uid, geteuid(2). of the application should be of sufficient privilege to perform such tasks as creating or mounting the user's home directory for example.
The flags argument is the binary or of zero or more of the following values:
Do not emit any messages.