pmTraversePMNS (3) - Linux Manuals

pmTraversePMNS: traverse the performance metrics name space

NAME

C SYNOPSIS

int pmTraversePMNS(const char *name, void (*dometric)(const char *));
int pmTraversePMNS_r(const char *name, void (*dometric_r)(const char *, void *), void *closure);

cc ... -lpcp

DESCRIPTION

The routine pmTraversePMNS may be used to perform a depth-first traversal of the Performance Metrics Name Space (PMNS).

The traversal starts at the node identified by name - if name is an empty string (i.e. ""), the traversal starts at the root of the PMNS. Usually name would be the pathname of a non-leaf node in the PMNS.

For each leaf node (i.e. performance metric) found in the traversal, the user-supplied routine dometric is called with the full pathname of that metric in the PMNS as the single argument. This argument is null-byte terminated, and is constructed from a buffer that is managed internally to pmTraversePMNS. Consequently the value is only valid during the call to dometric - if the pathname needs to be retained, it should be copied using strdup(3) before returning from dometric.

The pmTraversePMNS_r routine performs the same function, except the callback method func_r has an additional parameter that will be closure from the initial call to pmTraversePMNS_r. The additional parameter to pmTraversePMNS_r and the callback method allows the caller to pass context through pmTraversePMNS_r and into the callback method func_r, making the service more useful for multi-threaded applications where thread-private data can be accessed in the callback method via the closure argument.

On success pmTraversePMNS returns the number of children of name, which may be zero.

DIAGNOSTICS

PM_ERR_NOPMNS

Failed to access a PMNS for operation. Note that if the application hasn't a priori called pmLoadNameSpace(3) and wants to use the distributed PMNS, then a call to pmTraversePMNS must be made inside a current context.

PM_ERR_NAME

The initial pathname name is not valid in the current PMNS.

PM_ERR_*

Other diagnostics are for protocol failures when accessing the distributed PMNS.