On Tue, 2014-02-18 at 17:51 +0100, Paolo Bonzini wrote: > Il 18/02/2014 17:46, Marcel Apfelbaum ha scritto: > > Sometimes is not enough to get property's value, > > but it is needed to know if the value was actually set. > > > > This is especially useful when querying bool properties > > and having different defaults on different scenarios. > > I think this needs to go together with the use, so that I can understand > what exactly you need. It is used to replace qemu_opt_get_bool that provides a parameter for a default value. In this case we need to differentiate "no value" from "false."
I could send it with QemuMachine QOMify feature, but this will be a fairly large series and I *really* want to minimize it as much as I can, this is why I release small, stand-alone patches, that fixes some issue (see [Qemu-devel] [PATCH] qapi: output visitor crashes qemu if it encounters a NULL value), or adds a fairly useful feature like this one. I understand the downside of adding a feature without using it, but in the same time I want to get maintainers feedback and make my series as small as possible, bigger ones are harder to submit. Thanks for the review! Marcel > > Is it because the bool property is "bool *" and thus cannot be set to > (for example) -1 to indicate the default value? Exactly, but I suppose it can match every property that all its value range is valid. > > Paolo
