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 idea.


       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.

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 2023-12-22.
       (At that time, the date of the most recent commit that was found
       in the repository was 2023-12-16.)  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)

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