упрощенная выборка и преобразование значений показателей производительности  (simplified performance metrics value fetch and conversion)
  
Синопсис C (C Synopsis)
#include <pcp/pmapi.h>
       int pmCreateFetchGroup(pmFG *ptr, int type, const char *name);
       int pmExtendFetchGroup_item(pmFG pmfg, const char *metric, const
               char *instance, const char *scale, pmAtomValue
               *out_value, int out_type, int out_sts);
       int pmExtendFetchGroup_indom(pmFG pmfg, const char *metric, const
               char *scale, int out_inst_codes[], char
               *out_inst_names[], pmAtomValue out_values[], int
               out_type, int out_stss[], unsigned int out_maxnum,
               unsigned int *out_num, int *out_sts);
       int pmExtendFetchGroup_event(pmFG pmfg, const char *metric, const
               char *instance, const char *field, const char *scale,
               struct timespec out_times[], pmAtomValue out_values[],
               int out_type, int out_stss[], unsigned int out_maxnum,
               unsigned int *out_num, int *out_sts);
       int pmExtendFetchGroup_timestamp(pmFG pmfg, struct timeval
               *out_value);
       int pmGetFetchGroupContext(pmFG pmfg);
       int pmFetchGroup(pmFG pmfg);
       int pmClearFetchGroup(pmFG pmfg);
       int pmDestroyFetchGroup(pmFG pmfg);
       cc ... -lpcp