DOKK / manpages / debian 11 / libpcp-pmda3-dev / pmdaSendError.3.en
PMDASENDERROR(3) Library Functions Manual PMDASENDERROR(3)

pmdaSendError - send an error PDU to PMCD

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

void pmdaSendError(pmdaInterface *dispatch, int err);

cc ... -lpcp_pmda -lpcp

from pcp.pmda import PMDA
PMDA.pmda_notready()
PMDA.pmda_ready()

As part of the Performance Metrics Domain Agent (PMDA) API (see PMDA(3)), this routine allows a PMDA to send an error PDU to PMCD. There is presently only one use for this - so the PMDA can inform PMCD that it is ready (or not ready) to process requests.

The protocol details are described in pmcd(1) and PMDA(3), but basically if a PMDA starts in the notready state (as may be specified in pmcd.conf, see pmcd(1)) then PMCD will not send it any requests until the PMDA sends an PM_ERR_PMDAREADY error PDU using this function. This is used by a PMDA that may have a long startup time, e.g. to process a large configuration file or similar.

PMAPI(3), PMDA(3), pmcd(1), and pmdaopenmetrics(1).

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