Re: [Boost-users] Casting a shared_ptr as a prototyped (void *)?

On Jan 16, 2008 5:22 PM, Elli Barasch wrote:

Richard Dingwall wrote:

On Jan 16, 2008 1:11 PM, Elli Barasch wrote:

I'd like to pass a shared_ptr as the entry argument to a thread function via pthread_create. However, the entry argument is prototyped as void *. I can't simply cast the shared pointer as a (void *). How do I go about this?

Try passing:

static_cast(your_ptr.get())

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A follow up question. Does get() increase the reference count, or does it simply return the underlying pointer without doing so? If so, I'd be worried that a race exists such that the object could be destroyed before the thread gets to run.

get() does not incremement the reference count, as it returns a raw pointer, and there is no way of knowing how a raw pointer is being consumed or stored. If you the function you are passing it to retains a reference to the pointer anywhere, there is no way this can be tracked by the shared_ptr. Furthermore, if the shared_ptr(s) go out of scope the raw pointer references will be left dangling. HTH, Richard