__pmConnectLogger - connect to a performance metrics logger control
int __pmConnectLogger(const char *hostname, int pid)
cc ... -lpcp
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
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.
pmcd(1), pmlc(1), pmlogger(1), PMAPI(3) and __pmControlLog(3).
no permission to connect to the specified pmlogger(1) instance
the designated pmlogger(1) instance does not exist
the requested control port is already in use