__pmconnectlogger(3) — Linux manual page


PMCONNECTLOGGER(3)      Library Functions Manual      PMCONNECTLOGGER(3)

NAME         top

       __pmConnectLogger - connect to a performance metrics logger
       control port

C SYNOPSIS         top

       #include "pmapi.h"
       #include "libpcp.h"

       int __pmConnectLogger(const char *hostname, int pid);

       cc ... -lpcp

CAVEAT         top

       This documentation is intended for internal Performance Co-Pilot
       (PCP) developer use.

       These interfaces are not part of the PCP APIs that are guaranteed
       to remain fixed across releases, and they may not work, or may
       provide different semantics at some point in the future.

DESCRIPTION         top

       Each instance of the Performance Co-Pilot (PCP) archive creation
       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

       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

       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.

DIAGNOSTICS         top

              no permission to connect to the specified pmlogger(1)

              the designated pmlogger(1) instance does not exist

              the requested control port is already in use

SEE ALSO         top

       pmcd(1), pmlc(1), pmlogger(1), PMAPI(3) and __pmControlLog(3).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at 
       ⟨http://www.pcp.io/⟩.  If you have a bug report for this manual
       page, send it to pcp@groups.io.  This page was obtained from the
       project's upstream Git repository
       ⟨https://github.com/performancecopilot/pcp.git⟩ on 2023-12-22.
       (At that time, the date of the most recent commit that was found
       in the repository was 2023-12-16.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Performance Co-Pilot               PCP                PMCONNECTLOGGER(3)

Pages that refer to this page: __pmcontrollog(3)