pmgetarchivelabel(3) — Linux manual page



NAME         top

       pmGetArchiveLabel - fetch the label record from a set of
       performance metrics archive logs

C SYNOPSIS         top

       #include <pcp/pmapi.h>

       int pmGetArchiveLabel(pmLogLabel *lp);

       cc ... -lpcp

DESCRIPTION         top

       Within the framework of the Performance Co-Pilot (PCP), archive
       logs of performance metrics values may be accumulated and saved
       using the program pmlogger(1).

       The routine pmGetArchiveLabel may be used to fetch the label
       record from a set of archive logs that has already been opened
       using pmNewContext(3), or pmDupContext(3), and thereby associated
       with the current Performance Metrics Application Programming
       Interface (PMAPI) context.

       The result returned via the pointer lp is a structure that must
       be pre-allocated by the caller and has the following format
       (defined in pmapi.h).

          * Label Record at the start of every log file
         typedef struct {
           int        ll_magic;    /* PM_LOG_MAGIC | log format version no. */
           pid_t      ll_pid;      /* PID of logger */
           struct timeval ll_start;/* start of this log */
           char       ll_hostname[PM_LOG_MAXHOSTLEN]; /* name of collection host */
           char       ll_tz[40];   /* $TZ at collection host */
         } pmLogLabel;

       For an application, the most useful information from the archive
       label is likely to be in the fields ll_start, ll_hostname or

       Note that the size of the ll_hostname field is PM_LOG_MAXHOSTLEN
       (64 bytes) which is less than MAXHOSTNAMELEN (see
       gethostbyname(3)) on some platforms.  These semantics are
       necessary to retain backwards compatibility with the PCP archive
       file format.

       pmGetArchiveLabel returns zero for success.

DIAGNOSTICS         top

              the current PMAPI context is either invalid, or not
              associated with a set of archive logs


       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         top

       pmlogger(1), PMAPI(3), pmDupContext(3), pmGetConfig(3),
       pmNewContext(3), pcp.conf(5) and pcp.env(5).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual
       page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨⟩ on 2021-08-27.
       (At that time, the date of the most recent commit that was found
       in the repository was 2021-08-27.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Performance Co-Pilot               PCP              PMGETARCHIVELABEL(3)

Pages that refer to this page: pmgetarchiveend(3)pmgetcontexthostname(3)__pmparsetime(3)pmparsetimewindow(3)