On Sun, 14 Jan 2024 01:03:14 GMT, David Holmes <[email protected]> wrote:
>> src/hotspot/share/services/diagnosticCommand.cpp line 866:
>>
>>> 864: const char* filename = _filename.value();
>>> 865: if (strncmp(filename, DEFAULT_PERFMAP_FILENAME,
>>> strlen(DEFAULT_PERFMAP_FILENAME)) == 0) {
>>> 866: filename = nullptr; // use the default filename based on the pid
>>
>> Nit: the indent has to be 2, not 4.
>
> I only expected to see a change to the help string, I don't understand why
> the actual Dcmd is being modified here! ???
The default value for the argument is what gets displayed in the help text. For
example:
ThreadDumpToFileDCmd::ThreadDumpToFileDCmd(outputStream* output, bool heap) :
DCmdWithParser(output, heap),
_overwrite("-overwrite", "May overwrite existing file", "BOOLEAN", false,
"false"),
_format("-format", "Output format ("plain" or "json")", "STRING", false,
"plain"),
_filepath("filepath", "The file path to the output file", "STRING", true) {
_dcmdparser.add_dcmd_option(&_overwrite);
_dcmdparser.add_dcmd_option(&_format);
_dcmdparser.add_dcmd_argument(&_filepath);
}
And the help text:
Options: (options must be specified using the <key> or <key>=<value> syntax)
-overwrite : [optional] May overwrite existing file (BOOLEAN, false)
-format : [optional] Output format ("plain" or "json") (STRING, plain)
The help output that indicates that "plain" is the default format comes from
the intialization of the _format argument. There is no separate help text.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/17359#discussion_r1451636226
