NAME

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

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmGetArchiveLabel(pmLogLabel *lp);

       cc ... -lpcp

DESCRIPTION

       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 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.

DIAGNOSTICS

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

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.

SEE ALSO

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

Performance Co-Pilot                                   PCP                                  PMGETARCHIVELABEL(3)