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__pmlookupipc(3) — Linux manual page

PMLOOKUPIPC(3)           Library Functions ManualPMLOOKUPIPC(3)

NAME        top

__pmOverrideLastFd,__pmPrintIPC,__pmResetIPC- IPC version       infrastructure support

C SYNOPSIS        top

#include "pmapi.h"#include "libpcp.h"void __pmOverrideLastFd(intfd);void __pmPrintIPC(void);void __pmResetIPC(intfd);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

       IPC channels throughout the distributed PCP framework are affected       by the PCP 2.0 (and later) PDU changes.  These functions  are  the       interface  to  the  libpcp  IPC connection management global data.       This data consists of a hash table of __pmIPC structures  (indexed       by file descriptor) and a cached, most-recently-used file descrip‐       tor.       The__pmOverrideLastFdis  an  escape mechanism for use in those       situations where the last PDU fetch did not go through  the  usual       channels  (i.e.  __pmGetPDU), so as to ensure that the cached file       descriptor is the correct file descriptor for  the  PDU  which  is       currently  being  processed.   This  will  typically  be  used for       archive PDU processing or where version information is not  avail‐       able  for a given file descriptor (e.g. immediately prior to a PDU       version exchange).__pmPrintIPCis a useful debugging routine for displaying a  table       mapping all currently registered file descriptors to their associ‐       ated  PDU  version  numbers.   Unused entries in this table should       display the value zero in the version column.__pmResetIPCresets the version information  associated  with  the       given  file descriptor to some known (invalid) number.  Subsequent       lookups on this file descriptor will return an UNKNOWN_VERSION em‐       bedded within the __pmIPC structure.

DIAGNOSTICS        top

       A negative return value from__pmOverrideLastFdindicates that the       file descriptor argument is not  registered  in  the  hash  table.       This  typically indicates closure of an IPC channel, so PM_ERR_IPC       is returned if this is the case.

SEE ALSO        top

PMAPI(3)

COLOPHON        top

       This page is part of thePCP (Performance Co-Pilot) project.   In‐       formation  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       2025-08-11.  (At that time, the date of  the  most  recent  commit       that was found in the repository was 2025-08-11.)  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  isnot part of the original manual page), send a       mail to man-pages@man7.orgPerformance Co-Pilot               PCPPMLOOKUPIPC(3)

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