Given a valid PCP context identifier previously created with
pmNewContext(3) or pmDupContext(3), the pmGetContextHostName function
returns the hostname associated with id. The pmGetContextHostName_r
function does the same, but stores the result in a user-supplied
buffer buf of length buflen, which should have room for at least
MAXHOSTNAMELEN bytes. The pmGetHostName function behaves similarly
again, but returns a status code to indicate success or failure.
If the context id is associated with an archive source of data, the
hostname returned is extracted from the archive label using
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.
If id is not a valid PCP context identifier, the returned hostname is
a zero length string.
On failure, the return code of pmGetHostName is a negative PMAPI
error code which can be processed by pmErrStr_r(3) for diagnostics
relating to the failure to obtain the context hostname.
pmGetContextHostName returns a pointer to a static buffer, so the
returned value is only valid until the next call to
pmGetContextHostName and hence is not thread-safe. Multi-threaded
applications should use pmGetHostName or pmGetContextHostName_r
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(5). Values for these
variables may be obtained programmatically using the pmGetConfig(3)
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
email@example.com. This page was obtained from the project's upstream
Git repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
2020-06-09. (At that time, the date of the most recent commit that
was found in the repository was 2020-06-09.) If you discover any
rendering problems in this HTML version of the page, or you believe
there is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
Performance Co-Pilot PCP PMGETCONTEXTHOSTNAME(3)