MMV_INC_VALUE(3) Library Functions Manual MMV_INC_VALUE(3)

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

#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

mmv_inc_value and mmv_inc_atomvalue provide convenient ways of updating 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.

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

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