NAME¶
__pmConnectLogger - connect to a performance metrics logger control port
C SYNOPSIS¶
#include <pcp/pmapi.h>
#include <pcp/impl.h>
int __pmConnectLogger(const char *
hostname, int
pid);
cc ... -lpcp
DESCRIPTION¶
Each instance of the Performance Co-Pilot (PCP) archive logger program
pmlogger(1) supports a control port on which
__pmControlLog(3)
requests are received, and responses sent. Optionally, the
pmlogger(1)
instance may be designated the ``primary'' logger.
__pmConnectLogger may be used to establish a control port connection to
the
pmlogger(1) instance identified by process id
pid on the
host
hostname.
One special case is supported; for the reserved
pid value of
PM_LOG_CONTROL_PORT the requested connection is to the control port for
the ``primary'' logger, whatever its process id might be.
On success,
__pmConnectLogger returns a non-negative integer, that is a
file descriptor that may be used in subsequent communication with the
pmlogger(1) instance, e.g. for
__pmControlLog(3).
As the control port to
pmlogger(1) is not mulitplexed, applications using
__pmConnectLogger should use
close(2) to terminate the
connection to
pmlogger(1) as soon as they have finished communicating.
If the application connects, and the
pmlogger(1) instance subsequently
terminates, e.g. because the associated
pmcd(1) instance is terminated,
the application will have to explicitly re-establish connection to a
re-started
pmlogger(1) instance by calling
__pmConnectLogger
again.
SEE ALSO¶
pmcd(1),
pmlc(1),
pmlogger(1),
PMAPI(3) and
__pmControlLog(3).
DIAGNOSTICS¶
- PM_ERR_PERMISSION
- no permission to connect to the specified pmlogger(1) instance
- -ECONNREFUSED
- the designated pmlogger(1) instance does not exist
- -EEADDRINUSE
- the requested control port is already in use
