найти логический конец файла для набора архивных журналов (locate logical end of file for a set of archive logs)
Имя (Name)
pmGetArchiveEnd - locate logical end of file for a set of archive
logs
Синопсис C (C Synopsis)
#include <pcp/pmapi.h>
int pmGetArchiveEnd(struct timeval *tvp);
cc ... -lpcp
Описание (Description)
Assuming the current PMAPI context is associated with a set of
archive logs, 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 tvp. This
timestamp may be passed to pmSetMode(3) to reliably position the
context at the last valid log record, e.g. in preparation for
subsequent reading in reverse chronological order.
For archive logs that are not concurrently being written, the
physical end of file and the logical end of file are co-incident.
However if an archive log is being written by pmlogger(1) at the
same time an application 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 returns 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 tvp is well-
defined.
pmGetArchiveEnd preserves the positioning state of the log file
prior to this function call.
Диагностика (Diagnostic)
PM_ERR_NOCONTEXT
the current PMAPI context is either invalid, or not
associated with an set of archive logs
PM_ERR_LOGREC
the set of archives is sufficiently damaged, that not a
single valid record can be found
Окружение PCP (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.
Смотри также (See also)
PMAPI(3), pmFetch(3), pmFetchArchive(3), pmGetArchiveLabel(3),
pmGetConfig(3), pmSetMode(3), pcp.conf(5) and pcp.env(5).
