pmgetcontexthostname(3) [centos man page]

PMGETCONTEXTHOSTNAME(3) 				     Library Functions Manual					   PMGETCONTEXTHOSTNAME(3)

NAME

       pmGetContextHostName - return the hostname associated with a Performance Co-Pilot context

C SYNOPSIS

       #include <pcp/pmapi.h>

       const char *pmGetContextHostName(int id);

       cc ... -lpcp

DESCRIPTION

       Given  a valid PCP context identifier previously created with pmNewContext(3) or pmDupContext(3), the pmGetContextHostName function returns
       the hostname associated with id.

       If the context id is associated with an archive source  of  data,  the  hostname  returned  is  extracted  from	the  archive  label  using
       pmGetArchiveLabel(3).

       For  live  contexts,  an  attempt  will	first  be  made  to  retrieve the hostname from the PCP collector system using pmFetch(3) with the
       pmcd.hostname metric.  This allows client tools using this interface to retrieve an accurate host identifier even in the presence  of  port
       forwarding and tunnelled connections.

       Should  this not succeed, then a fallback method is used.  For local contexts - with local meaning any of DSO, ``localhost'' or Unix domain
       socket connection - a hostname will be sought via gethostname(3).  For other contexts, the hostname extracted from the initial context host
       specification will be used.

RETURN VALUE

       If id is not a valid PCP context identifier, this function returns a zero length string and hence never fails.

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	configura-
       tion file, as described in pcp.conf(5).	Values for these variables may be obtained programmatically using the pmGetConfig(3) function.

SEE ALSO

       PCPIntro(1), PMAPI(3), gethostname(3), pmDupContext(3), pmFetch(3), pmGetArchiveLabel(3), pmNewContext(3), pcp.conf(5) and pcp.env(5).

Performance Co-Pilot							PCP						   PMGETCONTEXTHOSTNAME(3)

PMGETARCHIVEEND(3)					     Library Functions Manual						PMGETARCHIVEEND(3)

NAME

       pmGetArchiveEnd - locate logical end of file for an archive log

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmGetArchiveEnd(struct timeval *tvp);

       cc ... -lpcp

DESCRIPTION

       Assuming  the  current PMAPI context is associated with an archive log, pmGetArchiveEnd will attempt to find the logical end of file (after
       the last complete record in the archive), and return the last recorded timestamp via tvp.  This timestamp may be passed to pmSetMode(3)	to
       reliably position the context at the last valid log record, e.g. in preparation for subsequent reading in reverse chronological order.

       For archive logs that are not concurrently being written, the physical end of file and the logical end of file are co-incident.	However if
       an archive log is being written by pmlogger(1) at the same time an application is trying to read the archive, the logical end of  file  may
       be before the physical end of file due to write buffering that is not aligned with the logical record boundaries.

       pmGetArchiveEnd	returns  an  error less than zero if the context is neither valid, nor associated with an archive, or the archive is seri-
       ously corrupted.  Otherwise, the return value is 0 if there has been no change of state since the last call, or 1 if  the  logical  end	of
       file has advanced since the last call.

       In the absence of an error, the result returned via tvp is well-defined.

       pmGetArchiveEnd preserves the positioning state of the log file prior to this function call.

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	configura-
       tion file, as described in pcp.conf(5).	Values for these variables may be obtained programmatically using the pmGetConfig(3) function.

SEE ALSO

       PMAPI(3), pmFetch(3), pmFetchArchive(3), pmGetArchiveLabel(3), pmGetConfig(3), pmSetMode(3), pcp.conf(5) and pcp.env(5).

DIAGNOSTICS

       PM_ERR_NOCONTEXT
	      the current PMAPI context is either invalid, or not associated with an archive log

       PM_ERR_LOGREC
	      the archive is sufficiently damaged, that not a single valid record can be found

Performance Co-Pilot							PCP							PMGETARCHIVEEND(3)