PMLOOKUPIPC(3)             Library Functions Manual             PMLOOKUPIPC(3)

NAME
       __pmOverrideLastFd, __pmPrintIPC, __pmResetIPC - IPC version
       infrastructure support

C SYNOPSIS
       #include "pmapi.h"
       #include "libpcp.h"

       void __pmOverrideLastFd(int fd);
       void __pmPrintIPC(void);
       void __pmResetIPC(int fd);

       cc ... -lpcp

CAVEAT
       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
       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 descriptor.

       The __pmOverrideLastFd is 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 available for a given
       file descriptor (e.g. immediately prior to a PDU version exchange).

       __pmPrintIPC is a useful debugging routine for displaying a table
       mapping all currently registered file descriptors to their associated
       PDU version numbers.  Unused entries in this table should display the
       value zero in the version column.

       __pmResetIPC resets 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 embedded within the
       __pmIPC structure.

DIAGNOSTICS
       A negative return value from __pmOverrideLastFd indicates 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
       PMAPI(3)

Performance Co-Pilot                  PCP                       PMLOOKUPIPC(3)