---
name: "pmdaSendError"
section: "3"
platform: "linux"
package: "pcp"
version: "7.2.2-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pmdaSendError"
---

# pmdaSendError(3)

send an error PDU to PMCD

## NAME

**pmdaSendError** - send an error PDU to PMCD

## C SYNOPSIS

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

**void pmdaSendError(pmdaInterface \****dispatch***, int** *err***);**

**cc ... -lpcp\_pmda -lpcp**

## PYTHON SYNOPSIS

**from pcp.pmda import PMDA**\
 **PMDA.pmda\_notready()**\
 **PMDA.pmda\_ready()**

## DESCRIPTION

As part of the Performance Metrics Domain Agent (PMDA) API (see [**PMDA**(3)](/PMDA/3.md)), 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)](/pmcd/1.md) and [**PMDA**(3)](/PMDA/3.md), but basically if a PMDA starts in the *notready* state (as may be specified in **pmcd.conf**, see [**pmcd**(1)](/pmcd/1.md)) 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.

## SEE ALSO

[**PMAPI**(3)](/PMAPI/3.md), [**PMDA**(3)](/PMDA/3.md), [**pmcd**(1)](/pmcd/1.md), and [**pmdaopenmetrics**(1)](/pmdaopenmetrics/1.md).