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
Man(1) output converted with
man2html