PMSTORE(3)

NAME
pmStore - modify values of performance metrics

C SYNOPSIS
#include <pcp/pmapi.h>

int pmStore(const pmResult *result);

cc ... -lpcp

DESCRIPTION
In some special cases it may be helpful to modify the current values of performance metrics, e.g. to reset a counter to zero, or to modify a ``metric'' which is a control variable for some agent collecting performance metrics.

pmStore is a lightweight inverses of pmFetch(3).

The caller must build the result data structure (of course, this could have been returned from an earlier pmFetch(3) call).

It is an error to pass a result to pmStore in which the field within any of the pmValueSet structures has a value less than one.

The current Performance Metrics Application Programming Interface (PMAPI) context must be one with a host as the source of metrics, and the current value of the nominated metrics will be changed, i.e. pmStore cannot be used to make retrospective changes to information in either the archives, or in the recent past for real-time sources of metrics.

The return code from pmStore is zero for success.

DIAGNOSTICS

PM_ERR_GENERIC
    At least one of the modifications was rejected. No other status is available from below the PMAPI (this is the lightweight part of the functionality!). In cases where the outcome of storing into individual metrics is important, the caller should make one call to either pmStore for each metric. On the other hand, a bulk modification can be performed in a single call for situations in which the outcome is not critical.

PM_ERR_NOTHOST
    The current PMAPI context is an archive rather than a host, or it is a host that is not set to the current time, i.e. has been ``rewound'' to the recent past using pmSetMode(3).

PM_ERR_TOOSMALL
    The number of metrics specified in result is less than one.

PM_ERR_VALUE
    One or more of the in result has a field with a value less than one.

COMPATIBILITY
Prior to PCP 7.0 the timestamp field in the pmResult struct was a struct timeval. To support PMAPI transition, the old interface and semantics can be used if applications are recompiled with -DPMAPI_VERSION=2.

For a time in PCP 6.x there was a routine with the same semantics as the current pmStore called pmStoreHighRes, and a struct with the same definition as the current pmResult struct called pmResultHighRes, although both are now deprecated and compile-time support for pmStoreHighRes and pmResultHighRes will be removed in a future release.

SEE ALSO
PMAPI(3), pmFetch(3), and pmSetMode(3).