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