PMDASENDERROR(3)

💖 PMDASENDERROR 💖

okay bestie, welcome to the PMDASENDERROR page from the Library Functions Manual — it's short, it's sweet, and it's literally the "hey PMCD, I'm awake!!" button. let's get into it 🫶

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✨ NAME ✨

pmdaSendError — send an error PDU to PMCD 🌸

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✨ C SYNOPSIS ✨

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

void pmdaSendError(pmdaInterface *dispatch, int err);

cc ... -lpcp_pmda -lpcp

so like, you grab those two headers, you call pmdaSendError() with a pmdaInterface *dispatch and an int err, and you link against -lpcp_pmda and -lpcp. that's the whole vibe 💅

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✨ PYTHON SYNOPSIS ✨

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

python girlies, you don't even touch pmdaSendError directly — you get these two cutie methods instead. no cap. 🐍

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✨ DESCRIPTION ✨

okay so as part of the Performance Metrics Domain Agent (PMDA) API (peep PMDA(3) for the full lore), this routine lets a PMDA send an error PDU over to PMCD. 📨

and like… there's presently only one use for this — it's so the PMDA can tell PMCD that it is ready (or not ready) to process requests. that's it. that's the whole job. iconic behavior honestly 👑

the protocol details live in pmcd(1) and PMDA(3), but basically: if a PMDA starts in the notready state (which 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. like, PMCD is respectfully waiting for the text back. 📵

and why would you ever want that?? because a PMDA might have a long startup time, e.g. to process a large configuration file or similar. so you go notready → do your little startup ritual → then hit it with the ready PDU and everyone's happy. 🌈✨

fr fr, if you forget to send that PM_ERR_PMDAREADY, PMCD just keeps ignoring you. awkward. 💀

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✨ SEE ALSO ✨

• PMAPI(3)
• PMDA(3)
• pmcd(1)
• pmdaopenmetrics(1)

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and that's the page, bestie!! this little baddie comes to you from Performance Co-Pilot — the PCP girlies — and it's filed under PMDASENDERROR(3). go forth and send your error PDUs responsibly 💖🎀🦋