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) configuration 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, security 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 environment, 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 configuration file, as described in pcp.conf(5). Values for these variables may be obtained programatically 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).