получить значения показателей производительности (get performance metric values)
Диагностика (Diagnostic)
As mentioned above, pmFetch and pmHighResFetch return error codes
insitu in the argument result. If no result is returned, e.g.
due to IPC failure using the current PMAPI context, or end of
file on an archive log, then these routines will return a
negative error code which may be examined using pmErrStr(3).
PM_ERR_NYI
Currently PCP archives do not support high resolution
timestamps, until this is addressed when fetching records
from an archive log the pmHighResFetch will fail with the
not-yet-implemented error code.
PM_ERR_EOL
When fetching records from an archive log, pmFetch returns
this error code to indicate the end of the log has been
passed (or the start of the log has been passed, if the
direction of traversal is backwards in time). If the
``mode'' for the current PMAPI context (see pmSetMode(3))
is PM_MODE_INTERP then the time origin is advanced, even
when this error code is returned. In this way
applications that position the time outside the range
defined by the records in the archive, and then commence
to pmFetch will eventually see valid results once the time
origin moves inside the temporal span of the archive.
