pmgetarchivelabel(3) — Linux manual page


PMGETARCHIVELABEL(3)      Library Functions Manual      PMGETARCHIVELABEL(3)

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)

       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

          * 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 ll_tz.

       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.


       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)

SEE ALSO         top

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

DIAGNOSTICS         top

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

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
       2020-11-01.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-10-30.)  If you discover any
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Performance Co-Pilot                 PCP                PMGETARCHIVELABEL(3)