1PMGETARCHIVELABEL(3)       Library Functions Manual       PMGETARCHIVELABEL(3)
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NAME

6       pmGetArchiveLabel  -  fetch  the label record from a set of performance
7       metrics archive logs
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C SYNOPSIS

10       #include <pcp/pmapi.h>
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12       int pmGetArchiveLabel(pmLogLabel *lp);
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14       cc ... -lpcp
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DESCRIPTION

17       Within the framework of the Performance Co-Pilot (PCP), archive logs of
18       performance  metrics values may be accumulated and saved using the pro‐
19       gram pmlogger(1).
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21       The routine pmGetArchiveLabel may be used to  fetch  the  label  record
22       from a set of archive logs that has already been opened using pmNewCon‐
23       text(3), or pmDupContext(3), and thereby associated  with  the  current
24       Performance Metrics Application Programming Interface (PMAPI) context.
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26       The result returned via the pointer lp is a structure that must be pre-
27       allocated by the caller  and  has  the  following  format  (defined  in
28       pmapi.h).
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30         /*
31          * Label Record at the start of every log file
32          */
33         typedef struct {
34           int        ll_magic;    /* PM_LOG_MAGIC | log format version no. */
35           pid_t      ll_pid;      /* PID of logger */
36           struct timeval ll_start;/* start of this log */
37           char       ll_hostname[PM_LOG_MAXHOSTLEN]; /* name of collection host */
38           char       ll_tz[40];   /* $TZ at collection host */
39         } pmLogLabel;
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41       For  an application, the most useful information from the archive label
42       is likely to be in the fields ll_start, ll_hostname or ll_tz.
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44       Note that the size of the ll_hostname field  is  PM_LOG_MAXHOSTLEN  (64
45       bytes) which is less than MAXHOSTNAMELEN (see gethostbyname(3)) on some
46       platforms.  These semantics are necessary to retain backwards  compati‐
47       bility with the PCP archive file format.
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49       pmGetArchiveLabel returns zero for success.
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PCP ENVIRONMENT

52       Environment variables with the prefix PCP_ are used to parameterize the
53       file and directory names used by PCP.  On each installation,  the  file
54       /etc/pcp.conf  contains  the  local  values  for  these variables.  The
55       $PCP_CONF variable may be used to specify an alternative  configuration
56       file,  as  described in pcp.conf(5).  Values for these variables may be
57       obtained programmatically using the pmGetConfig(3) function.
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SEE ALSO

60       pmlogger(1),  PMAPI(3),  pmDupContext(3),   pmGetConfig(3),   pmNewCon‐
61       text(3), pcp.conf(5) and pcp.env(5).
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DIAGNOSTICS

64       PM_ERR_NOCONTEXT
65              the  current  PMAPI context is either invalid, or not associated
66              with a set of archive logs
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70Performance Co-Pilot                  PCP                 PMGETARCHIVELABEL(3)
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