pmusecontext(3) [centos man page]

PMUSECONTEXT(3) 					     Library Functions Manual						   PMUSECONTEXT(3)

NAME

       pmUseContext - change current PMAPI context

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmUseContext(int handle);

       cc ... -lpcp

DESCRIPTION

       An  application	using  the  Performance Metrics Application Programming Interface (PMAPI) may manipulate several concurrent contexts, each
       associated with a source of performance metrics, e.g. pmcd(1) on some host, or an archive log of performance metrics as created	by  pmlog-
       ger(1).

       Calling	pmUseContext  causes  the  current  PMAPI  context to be set to the context identified by handle.  The value of handle must be one
       returned from an earlier call to pmNewContext(3) or pmDupContext(3).

       Below the PMAPI, all contexts used by an application are saved in their most recently modified state, so pmUseContext restores the  context
       to the state it was in the last time the context was used, not the state of the context when it was established.

SEE ALSO

       PMAPI(3), pmDestroyContext(3), pmDupContext(3), pmNewContext(3) and pmWhichContext(3).

DIAGNOSTICS

       PM_ERR_NOCONTEXT

	      handle does not identify a valid PMAPI context

Performance Co-Pilot							PCP							   PMUSECONTEXT(3)

PMTRIMNAMESPACE(3)					     Library Functions Manual						PMTRIMNAMESPACE(3)

NAME

       pmTrimNameSpace - prune a performance metrics name space

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmTrimNameSpace(void);

       cc ... -lpcp

DESCRIPTION

       If  the current Performance Metrics Application Programming Interface (PMAPI) context corresponds to a version 1 archive log of Performance
       Co-Pilot (PCP) performance metrics (as collected by pmlogger(1) -V1), then the currently loaded Performance Metrics Name Space  (PMNS),	is
       trimmed to exclude metrics for which no description can be found in the archive.  The PMNS is further trimmed to remove empty subtrees that
       do not contain any performance metric.

       Since PCP archives usually contain some subset of all metrics named in the default PMNS, pmTrimNameSpace  effectively  trims  the  applica-
       tion's PMNS to contain only the names of the metrics in the archive.

       Since PCP 2.0, pmTrimNameSpace is only needed for dealing with version 1 archives.  Version 2 archives actually store the "trimmed" PMNS.

       Prior to any trimming, the PMNS is restored to the state as of the completion of the last pmLoadASCIINameSpace(3) or pmLoadNameSpace(3), so
       the effects of consecutive calls to pmTrimNameSpace with archive contexts are not additive.

       If the current PMAPI context corresponds to a host and a pmLoadASCIINameSpace(3) or pmLoadNameSpace(3) call was made, then the PMNS reverts
       to all names loaded into the PMNS at the completion of the last pmLoadASCIINameSpace(3) or pmLoadNameSpace(3), i.e. any trimming is undone.

       On success, pmTrimNameSpace returns zero.

SEE ALSO

       pmlogger(1), PMAPI(3), pmLoadASCIINameSpace(3), pmLoadNameSpace(3), pmNewContext(3) and pmns(5).

DIAGNOSTICS

       PM_ERR_NOPMNS
	      you must have loaded a PMNS using pmLoadASCIINameSpace(3) or pmLoadNameSpace(3) before calling pmTrimNameSpace

       PM_ERR_NOCONTEXT
	      the current PMAPI context is invalid

Performance Co-Pilot							PCP							PMTRIMNAMESPACE(3)