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).