pmUseContext man page
pmUseContext — change current PMAPI context
int pmUseContext(int handle);
cc ... -lpcp
An application using the Performance Metrics Application Programming Interface (PMAPI) may manipulate several concurrent contexts, each associated with a source of performance metrics, e.g. pmcd(1) on some host, or an archive log of performance metrics as created by pmlogger(1).
Calling pmUseContext causes the current PMAPI context to be set to the context identified by handle. The value of handle must be one returned from an earlier call to pmNewContext(3) or pmDupContext(3).
Below the PMAPI, all contexts used by an application are saved in their most recently modified state, so pmUseContext restores the context to the state it was in the last time the context was used, not the state of the context when it was established.
PMAPI(3), pmDestroyContext(3), pmDupContext(3), pmNewContext(3) and pmWhichContext(3).
handle does not identify a valid PMAPI context
pmAddProfile(3), PMAPI(3), pmCreateFetchGroup(3), pmDelProfile(3), pmDestroyContext(3), pmDupContext(3), pmFetch(3), pmiStart(3), pmNewContext(3), pmReconnectContext(3), pmWhichContext(3), QmcGroup(3).