mmv_inc_value(3) — Linux manual page

MMV_INC_VALUE(3)         Library Functions Manual        MMV_INC_VALUE(3)

NAME         top

       mmv_inc, mmv_inc_value, mmv_inc_atomvalue - update a value in a
       Memory Mapped Value file

C SYNOPSIS         top

       #include <pcp/pmapi.h>
       #include <pcp/mmv_stats.h>

       void mmv_inc_value(void *addr, pmAtomValue *av, double inc);
       void mmv_inc_atomvalue(void *addr, pmAtomValue *av,
                              pmAtomValue *inc);

       cc ... -lpcp_mmv -lpcp

DESCRIPTION         top

       mmv_inc_value and mmv_inc_atomvalue provide convenient ways of up‐
       dating    a    metric    av    previously    returned    by    the
       mmv_lookup_value_desc(3) interface.  addr is the address  returned
       from mmv_stats_init(3).

       These interfaces are most commonly used with counter type metrics.
       Refer  to mmv_set_value(3) for a mechanism suited to instantaneous
       and discrete metrics.

       With mmv_inc_atomvalue the value provided via the inc pointer must
       match the type of the metric, and will be added  to  the  previous
       value of the metric.

       In  the  case of mmv_inc_value the value of inc is internally cast
       to match the type of the metric and then  added  to  the  previous
       value of the metric.

SEE ALSO         top

       mmv_set_value(3),  mmv_stats_init(3), mmv_lookup_value_desc(3) and
       mmv(5).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.   In‐
       formation  about the project can be found at ⟨http://www.pcp.io/⟩.
       If you have a  bug  report  for  this  manual  page,  send  it  to
       [email protected].  This page was obtained from the project's upstream
       Git  repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
       2025-08-11.  (At that time, the date of  the  most  recent  commit
       that was found in the repository was 2025-08-11.)  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 [email protected]

Performance Co-Pilot                                     MMV_INC_VALUE(3)

Pages that refer to this page: mmv_lookup_value_desc(3),  mmv_set_value(3),  mmv_stats_init(3),  mmv_stats_registry(3)

HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH.