Retrieving
Counter Names and Explanations
Object type
names, counter names, object explanations, and counter explanations are not
made directly available in the performance data structures. Instead, the
performance data structures contain indices you can use to locate where the
names and explanations for each object and counter can be found. The ObjectNameTitleIndex
and ObjectHelpTitleIndex members of the PERF_OBJECT_TYPE structure contain the
indices to the object name and explanation, respectively. The CounterNameTitleIndex
and CounterHelpTitleIndex members of the PERF_COUNTER_DEFINITION structure contain the
indices to the counter name and explanation, respectively.
To access the
names and explanations, read the Counter and Help values in the
following registry key.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT
\CurrentVersion\Perflib\langid
The langid
is the ASCII representation of the 3-digit hexadecimal language identifier. For
example, the U.S. English langid is 009. In a non-English version of
Windows NT, counters are stored in both the native language of the system and
in English.
The data is
stored as MULTI_SZ strings. This data type consists of a list of Unicode
strings, each terminated with UNICODE_NULL. The last string is followed by an
additional UNICODE_NULL. The strings are listed in pairs. The first string of
each pair is the Unicode string of the index, and the second string is the
actual name of the index. The Counter data uses only even-numbered
indexes, while the Help data has odd-numbered indexes. For example, the Counter
data contains the following object and counter name strings.
2 System
4 Memory
6 %
Processor Time
The Help
data contains the following counter explanations.
3 The
System object type includes those counters that...
5 The
Memory object type includes those counters that...
7 Processor
Time is expressed as a percentage of the...
To retrieve a
name or explanation for an object type or counter, given its index, an
application should perform the following steps.
1. If the system is remote, call the RegConnectRegistry function.
2. Use the RegOpenKeyEx function to open the
registry key containing the name and explanation text.
3. Use the RegQueryValueEx function, specifying
either Counter or Help as the name of the value to query.
4. Convert the index into Unicode or ASCII,
depending on whether your application is Unicode or ASCII.
5. Search the MULTI_SZ data for the appropriate
index.
6. Retrieve the string following the matching
index. The string contains the name or explanation.
If you are
going to be looking up a number of counters, you should build a table for
faster and easier lookup. For an example, see Displaying Object, Instance,
and Counter Names.