1PMGETARCHIVEEND(3)         Library Functions Manual         PMGETARCHIVEEND(3)
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NAME

6       pmGetArchiveEnd - locate logical end of file for a set of archive logs
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C SYNOPSIS

9       #include <pcp/pmapi.h>
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11       int pmGetArchiveEnd(struct timeval *tvp);
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13       cc ... -lpcp
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DESCRIPTION

16       Assuming  the current PMAPI context is associated with a set of archive
17       logs, pmGetArchiveEnd will attempt to find  the  logical  end  of  file
18       (after the last complete record in the set of archives), and return the
19       last recorded timestamp via tvp.   This  timestamp  may  be  passed  to
20       pmSetMode(3)  to  reliably  position  the context at the last valid log
21       record, e.g. in preparation for subsequent reading in  reverse  chrono‐
22       logical order.
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24       For  archive logs that are not concurrently being written, the physical
25       end of file and the logical end of file are co-incident.  However if an
26       archive  log is being written by pmlogger(1) at the same time an appli‐
27       cation is trying to read the archive, the logical end of  file  may  be
28       before  the  physical  end  of  file due to write buffering that is not
29       aligned with the logical record boundaries.
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31       pmGetArchiveEnd returns an error less than zero if the context is  nei‐
32       ther  valid,  nor  associated with a set of archives, or the set of ar‐
33       chives is seriously corrupted.  Otherwise, the return  value  is  0  if
34       there has been no change of state since the last call, or 1 if the log‐
35       ical end of file has advanced since the last call.
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37       In the absence of an error,  the  result  returned  via  tvp  is  well-
38       defined.
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40       pmGetArchiveEnd  preserves  the positioning state of the log file prior
41       to this function call.
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PCP ENVIRONMENT

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

52       PMAPI(3),  pmFetch(3),  pmFetchArchive(3), pmGetArchiveLabel(3), pmGet‐
53       Config(3), pmSetMode(3), pcp.conf(5) and pcp.env(5).
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DIAGNOSTICS

56       PM_ERR_NOCONTEXT
57              the current PMAPI context is either invalid, or  not  associated
58              with an set of archive logs
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60       PM_ERR_LOGREC
61              the  set  of archives is sufficiently damaged, that not a single
62              valid record can be found
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