NAME¶
pmTraversePMNS,
pmTraversePMNS_r - traverse the performance
metrics name space
C SYNOPSIS¶
#include <pcp/pmapi.h>
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(3C) 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.
SEE ALSO¶
PMAPI(3) and
pmGetChildren(3).
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.
