In order to use only one command to get all labels defined in the vob, plus their date and comment, I use the command below and it works well.
cleartool lstype -fmt "%n;%d;%c" -kind lbtype -invob /vobs/myvob
Now, I would like to avoid to wait 13 minutes to get 40000 labels and I would like to get only the label created this month.
Unfortunately a range of date is not allowed as the type-selector
If I have to use another cleartool command instead of lstype, it is not a problem. I think about the command describe for example. But I didn't succeed to display all the labels in one shot with describe command.
I am not aware of a pure cleartool command for this.
For your use case, I would make a cron batch in order to maintain (every day or more frequently) a list of all labels by date, in order to process that list whenever I need.
That way, you don't have to query labels, just to read them.
This is very much a workaround, but one which could be enough for now.