NAME

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

C SYNOPSIS

       #include <pcp/pmapi.h>
       char *pmGetConfig(const char *variable);
       char *pmGetOptionalConfig(const char *variable);
       char *pmGetAPIConfig(const char *feature);

       cc ... -lpcp

DESCRIPTION

       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

       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.

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.

SEE ALSO

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