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pmgetarchivelabel(3) [centos man page]

PMGETARCHIVELABEL(3)					     Library Functions Manual					      PMGETARCHIVELABEL(3)

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)) on some platforms. 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 configura- tion file, as described in pcp.conf(5). Values for these variables may be obtained programmatically using the pmGetConfig(3) function. SEE ALSO
pmlogger(1), PMAPI(3), pmDupContext(3), pmGetConfig(3), pmNewContext(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 Performance Co-Pilot PCP PMGETARCHIVELABEL(3)

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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)

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