NAME

       pmGetDerivedControl, pmSetDerivedControl  - get and set controls for derived metrics

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmGetDerivedControl(int what, int *valuep);
       int pmSetDerivedControl(int what, int value);

       cc ... -lpcp

DESCRIPTION

       These  routines may be used to influence the behaviour of the derived metric services that
       are    activated    for    global    derived    metrics    using     pmRegisterDerived(3),
       pmRegisterDerivedMetric(3)  and  pmLoadDerivedConfig(3),  or  per-context  derived metrics
       using pmAddDerived(3) and pmAddDerivedDerived(3).

       The  what  argument  selects  a  control,  the  value  argument  provides  a   value   for
       pmSetDerivedControl   and   the   valuep   argument  is  used  to  return  the  value  for
       pmGetDerivedControl.

       The what argument has one of the following values:

       PCP_DERIVED_GLOBAL_LIMIT
              The maximum number of global derived metrics that may be  defined.   The  value  -1
              indicates no limit.

       PCP_DERIVED_CONTEXT_LIMIT
              The  maximum  number of per-context derived metrics that may be defined.  The value
              -1 indicates no limit.

       PCP_DERIVED_DEBUG_SYNTAX
              Debug diagnostics during parsing of derived metric expression.  The value 1 enables
              the diagnostics, the value 0 disables them.

       PCP_DERIVED_DEBUG_SEMANTICS
              Debug  diagnostics for semantic checks during the binding of metrics in the derived
              metric expression to the available metrics in a new PMAPI  context.   The  value  1
              enables the diagnostics, the value 0 disables them.

       PCP_DERIVED_DEBUG_EVAL
              Debug   diagnostics  when  derived  metrics  are  used  in  PMAPI  operations  like
              pmFetch(3),     pmGetChildren(3),     pmGetChildrenStatus(3),      pmLookupDesc(3),
              pmLookupName(3), pmNameAll(3), pmNameID(3) and pmTraversePMNS(3).

RETURN VALUES

       Both  routines  return  0  on  success, else a value less than 0 that can be decoded using
       pmErrStr(3).

SEE ALSO

       PCPIntro(1),    pmAddDerived(3),     pmAddDerivedMetric(3),     PMAPI(3),     pmErrStr(3),
       pmLoadDerivedConfig(3), pmRegisterDerived(3), pmRegisterDerivedMetric(3) and PMNS(5).