NAME

       pmGetArchiveEnd - locate logical end of file for a set of archives

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmGetArchiveEnd(struct timespec *tp);

       cc ... -lpcp

DESCRIPTION

       Assuming  the current PMAPI context is associated with a set of archives, pmGetArchiveEnd will attempt to
       find the logical end of file (after the last complete record in the set of archives), and return the last
       recorded timestamp via tp.  This timestamp may be passed to pmSetMode(3) to reliably position the context
       at the last valid archive record, e.g. in preparation for subsequent reading in reverse chronological or‐
       der.

       For archives that are not concurrently being written, the physical end of file and  the  logical  end  of
       file are co-incident.  However if an archive is being written by pmlogger(1) at the same time an applica‐
       tion is trying to read the archive, the logical end of file may be before the physical end of file due to
       write buffering that is not aligned with the logical record boundaries.

       pmGetArchiveEnd return an error less than zero if the context is neither valid, nor associated with a set
       of  archives,  or  the set of archives is seriously corrupted.  Otherwise, the return value is 0 if there
       has been no change of state since the last call, or 1 if the logical end of file has advanced  since  the
       last call.

       In the absence of an error, the result returned via tp is well-defined.

       Both pmGetArchiveEnd preserve the positioning state of the archive file prior to this function call.

COMPATIBILITY

       Prior  to PCP 7.0 and libpcp.so.4 the tp argument was a struct timeval.  To support PMAPI transition, the
       old interface and semantics can be used if applications are linked with libpcp.so.3  or  recompiled  with
       -DPMAPI_VERSION=2.

       For  a  time in PCP 6.x there was a routine with the same semantics as the current pmGetArchiveEnd called
       pmGetHighResArchiveEnd, although this  is  now  deprecated  and  compile-time  support  for  pmGetHighRe‐
       sArchiveEnd will be removed in a future release.

DIAGNOSTICS

       PM_ERR_NOCONTEXT
              the current PMAPI context is either invalid, or not associated with a set of archives

       PM_ERR_LOGREC
              the set of archives is sufficiently damaged, that not a single valid record can be found

PCP ENVIRONMENT

       Environment  variables with the prefix PCP_ are used to parameterize the file and directory names used by
       PCP.  On each installation, the file /etc/pcp.conf contains the local values for  these  variables.   The
       $PCP_CONF variable may be used to specify an alternative configuration file, as described in pcp.conf(5).
       Values for these variables may be obtained programmatically using the pmGetConfig(3) function.

SEE ALSO

       PMAPI(3),  pmFetch(3), pmFetchArchive(3), pmGetArchiveLabel(3), pmGetConfig(3), pmSetMode(3), pcp.conf(5)
       and pcp.env(5).

Performance Co-Pilot                                   PCP                                    PMGETARCHIVEEND(3)