int pmiAddMetric(const char * name , pmID pmid , int type , pmInDom indom , int sem , pmUnits units );
The other arguments are in effect the fields of a pmDesc structure. Refer to pmLookupDesc (3) for a complete description of the values and semantics of the components of this structure, and hence the valid argument values for pmiAddMetrics .
The internal identifier for the metric may be given using the pmid argument and must be unique for each LOGIMPORT context. The value for pmid which would typically be constructed using the pmid_build macro, e.g. pmid_build(PMI_DOMAIN, 0, 3) for the fourth metric in first ``cluster'' of metrics in the Performance Metrics Domain PMI_DOMAIN (which is the default for all meta data created by the LOGIMPORT library). Alternatively, pmid may be PM_IN_NULL and pmiAddMetric will assign a unique pmid (although this means the pmid remains opaque and the application must use pmiPutValue (3) or pmiPutValueHandle (3) and cannot use pmiPutResult (3) to add data values to the PCP archive).
type defines the data type of the metric and must be one of the PM_TYPE_... values defined in < pcp/import.h > .
The instance domain for the metric is defined by indom and may be PM_INDOM_NULL for a metric with a singular value, else the value for indom would normally be constructed using the pmInDom_build macro, e.g. pmInDom_build(LOGIMPORT,0) for the first instance domain in the Performance Metrics Domain LOGIMPORT (which is the default for all meta data created by the LOGIMPORT library). Multiple metrics can share the same instance domain if they have values for a similar (or more usually, identical) set of instances.
The semantics of the metric (counter, instantaneous value, etc.) is specified by the sem argument which would normally be the result of a call to the convenience constructor method pmiUnits (3).