пройти по пространству имен показателей производительности (traverse the performance metrics name space)
Имя (Name)
pmTraversePMNS, pmTraversePMNS_r - traverse the performance
metrics name space
Синопсис C (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
Описание (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 and pmTraversePMNS_r return the number
of leaf nodes found in the traversal, which will be one (1) if
name is either a leaf node, or a derived metric or a non-leaf
node with one child. If name is a non-leaf node, the returned
value will be zero or greater (zero is returned in the special
case where name is a dynamic root node that currently has no
children). In all cases, derived metrics present in the PMNS
subtree below name are counted as leaf-nodes. If an an error
occurs, pmTraversePMNS and pmTraversePMNS_r will return a
negative error code, as described in the DIAGNOSTICS section
below.
Диагностика (Diagnostic)
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.
Смотри также (See also)
PMAPI(3) and pmGetChildren(3).
