Normally pmlogger creates a socket to receive control messages
from pmlc(1) on the first available TCP/IP port numbered 4330 or
higher. The environment variable PMLOGGER_PORT may be used to
specify an alternative starting port number.
If set to the value 1, the PMLOGGER_LOCAL environment variable
will cause pmlogger to run in a localhost-only mode of operation,
where it binds only to the loopback interface.
The PMLOGGER_REQUEST_TIMEOUT variable may be set by applications
such as pmlc(1) to specify a timeout in seconds for connection
requests to the pmlogger control port. If not set, connections
may block indefinitely. This variable would not normally be set
by pmlogger itself.
The PMLOGGER_MAXPENDING variable can be set to indicate the
maximum length to which the queue of pending pmlc connections may
grow.
The default sampling interval used by pmlogger can be set using
the PMLOGGER_INTERVAL variable (if not set, 60 seconds will be
used). Both the command line and directives in the configuration
file will override this value. It is an integer in units of
seconds.
On platforms using systemd(1), and when the -N option is given,
the NOTIFY_SOCKET environment variable would normally be set by
the service manager prior to launching pmlogger.
