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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)

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PMGETCONFIG(3)						     Library Functions Manual						    PMGETCONFIG(3)

NAME
pmGetConfig - return Performance Co-Pilot configuration variable C SYNOPSIS
#include <pcp/pmapi.h> char *pmGetConfig(const char *variable); #include <pcp/impl.h> char *__pmGetAPIConfig(const char *feature); cc ... -lpcp DESCRIPTION
The pmGetConfig function searches for variable first in the environment and then, if not found, in the Performance Co-Pilot (PCP) configu- ration file and returns the string result. If variable is not already in the environment, it is added with a call to putenv(3) before returning. The default location of the PCP configuration file is /etc/pcp.conf but this may be changed by setting PCP_CONF in the environment to a new location, as described in pcp.conf(5). The internal __pmGetAPIConfig function reports on features of the PCP library. It can be used to query support for multi-threading, secu- rity extensions, and other features. The pmconfig(1) utility provides command line access to both of these interfaces, and also provides a mechanism for listing all available variables and features that are valid arguments to these routines. RETURN VALUE
If variable is not found in either the environment nor the PCP configuration file then the return value is an empty string. If the PCP configuration file is not found then a fatal error message is printed and the process will exit(2) - although this sounds drastic, it is the only course of action available because the PCP configuration/installation is fatally flawed. If the pmGetConfig function returns a non-empty string, the returned value points into the environment and so changing it is a bad idea. This function returns the same type as the getenv(3) function (which should probably be a const char *). The __pmGetAPIConfig routine on the other hand returns NULL on failure to lookup the requested feature. It does not modify the environ- ment, and returns a pointer to a static read-only string which also should not be modified or freed by the caller. 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), pmconfig(1), exit(2), PMAPI(3), getenv(3C), putenv(3C), pcp.conf(5), pcp.env(5) and environ(5). Performance Co-Pilot PCP PMGETCONFIG(3)

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