Debugging messages. These messages are normally not logged unless the global integer variable _openpam_debug is set to a non-zero value, in which case they are logged with a syslog(3) priority of LOG_DEBUG.
PAM_LOG_VERBOSE
Information about the progress of the authentication process, or other non-essential messages. These messages are logged with a syslog(3) priority of LOG_INFO.
PAM_LOG_NOTICE
Messages relating to non-fatal errors. These messages are logged with a syslog(3) priority of LOG_NOTICE.
PAM_LOG_ERROR
Messages relating to serious errors. These messages are logged with a syslog(3) priority of LOG_ERR.
The remaining arguments are a printf(3) format string and the corresponding arguments.
