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NAME

       pmGetArchiveLabel  -  fetch the label record from a performance metrics
       archive log

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 an archive log 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)) in
       IRIX6.5 or later.  These semantics are necessary  to  retain  backwards
       compatibility with the PCP archive file format.

       pmGetArchiveLabel returns zero for success.

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(4).  Values for these variables may be
       obtained programatically using the pmGetConfig(3) function.

SEE ALSO

       pmlogger(1),      PMAPI(3),      pmDupContext(3),       pmGetConfig(3),
       pmNewContext(3), pcp.conf(4) and pcp.env(4).

DIAGNOSTICS

       PM_ERR_NOCONTEXT
              the  current  PMAPI context is either invalid, or not associated
              with an archive log