pthread_t in 5.3

[Medi Montaseri]

I am confused about the pthread_t type in FreeBSD 5.3,  can you help..

Based on /usr/include/pthread.h,
typedef struct  pthread                 *pthread_t;
and when I look for the declaration of "struct pthread" , all I find is
a forward declaration with a comment that says,

/*
 * Forward structure definitions.
 *
 * These are mostly opaque to the user.
 */
struct pthread;

That is 'struct pthread' is an opaque type....
Then in my application, when I try to find my thread_id, I say

cout << "my tid is " << pthread_self() << endl;
and I get a hex value. Which is syntactically correct, but semantically 
in-correct.
I'm not interested in the pointer, I'm interested in the numerical 
thread ID...
Now at this point, you'll think all you have to do is to de-reference 
the pointer.
But since 'struct pthrad' is opaque, gdb and myself are clueless to 
proceed from here.
Can someone shed some light on this please...

Thanks