Boost.Thread and its synchronization classes

[IceDane]

I'm working on a multi-threaded application using Boost.Thread, and I've been wondering about something which I cannot find any concrete information about(due to the ambiguity of the only possible search query).

Basically, I'm trying to design my application so that it creates N threads, which all have sets of data that needs to be processed. When they finish, they alert my main thread and I give them new data.
To facilitate this, I'm using an object that contains all the necessary synchronization variables and so on, and this is where I've run into a strange situation that left me wondering.

The synchronization object looks something like this:

struct data
{
    mutex accessSync;
    string myData;
    condition_variable dataReadyCond;
    condition_variable threadDoneCond;
    bool dataReady;
    bool threadDone;
};

What I am wondering is why this doesn't seem to be valid(The error is in the mutex and/or condition_variable parts, I know that the other stuff is valid)

struct data d = {mutex(), "foo", condition_variable(), condition_variable(), false, false};

The fact that it isn't raises a question: If I create one of the the thread sync objects in question in main, as such:

mutex m;
// or
condition_variable cond;

They are both valid, fully created objects. What about the struct? I mean, if I create an instance of the struct like I did, are those objects initialized already? If not, why can't I do what I was trying to do above?

To fix the problem, I used shared_ptrs and allocated them dynamically, but it adds a lot of clutter to the code and I would really like to know if this could be done in this manner, with some modification, or at least know the explanation.

Thanks in advance!

[Codeplug]

>> What I am wondering is why this doesn't seem to be valid
What is the error? What compiler?

gg