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   pmGetHostName    ( 3 )

вернуть имя хоста, связанное с контекстом performance Co-Pilot (return the hostname associated with a performance Co-Pilot context)

Имя (Name)

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

Синопсис C (C Synopsis)

#include <pcp/pmapi.h>

int pmGetHostName(int id, char *buf, int buflen); const char *pmGetContextHostName(int id); char *pmGetContextHostName_r(int id, char *buf, int buflen);

cc ... -lpcp


Описание (Description)

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 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.


Возвращаемое значение (Return value)

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.


Примечание (Note)

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 instead.

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

Смотри также (See also)

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