pmgetconfig(3) — Linux manual page


PMGETCONFIG(3)            Library Functions Manual            PMGETCONFIG(3)

NAME         top

       pmGetConfig,  pmGetOptionalConfig, pmGetAPIConfig - return values for
       Performance Co-Pilot configuration variables

C SYNOPSIS         top

       #include <pcp/pmapi.h>

       char *pmGetConfig(const char *variable);
       char *pmGetOptionalConfig(const char *variable);
       char *pmGetAPIConfig(const char *feature);

       cc ... -lpcp

DESCRIPTION         top

       The pmGetConfig and pmGetOptionalConfig functions search 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 setenv(3) before returning.

       The pmGetOptionalConfig function allows for failures - either from
       variable not being set at all, or due to the configuration file being
       missing.  pmGetConfig is less tolerant to a missing configuration
       file, which it treats as a critical PCP installation failure - see
       the ``RETURN VALUE'' section below for further details.

       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 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         top

       If variable is not found in either the environment or the PCP
       configuration file, or if the configuration file is inaccessible,
       then pmGetOptionalConfig returns NULL.

       If variable is found in neither the environment nor the PCP
       configuration file, then pmGetConfig returns 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 deemed fatally flawed.

       The pmGetAPIConfig routine 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.

       The value returned by all of these routines is either a static
       pointer or pointer into the environment, and so changing it is a bad


       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)

SEE ALSO         top

       PCPIntro(1), pmconfig(1), pmGetVersion(3), exit(2), PMAPI(3),
       getenv(3), setenv(3), pcp.conf(5), pcp.env(5) and environ(7).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at ⟨⟩.
       If you have a bug report for this manual page, send it to  This page was obtained from the project's upstream
       Git repository ⟨⟩ on
       2020-11-01.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-10-30.)  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                      PMGETCONFIG(3)