NAME

       pmGetArchiveLabel  - fetch the label record from a perfor­
       mance 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 accumu­
       lated 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_MAX­
       HOSTLEN  (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

       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


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