Hello,
I have a question about the C language.
This piece of code is from the glibc library.
My question is about the static struct
The question is....
Are static structures automatically initialized ?
static struct random_data unsafe_state =
{
/* FPTR and RPTR are two pointers into the state info, a front and a rear
pointer. These two pointers are always rand_sep places aparts, as they
cycle through the state information. (Yes, this does mean we could get
away with just one pointer, but the code for random is more efficient
this way). The pointers are left positioned as they would be from the
call:
initstate(1, randtbl, 128);
(The position of the rear pointer, rptr, is really 0 (as explained above
in the initialization of randtbl) because the state table pointer is set
to point to randtbl[1] (as explained below).) */
.fptr = &randtbl[SEP_3 + 1],
.rptr = &randtbl[1],
/* The following things are the pointer to the state information table,
the type of the current generator, the degree of the current polynomial
being used, and the separation between the two pointers.
Note that for efficiency of random, we remember the first location of
the state information, not the zeroth. Hence it is valid to access
state[-1], which is used to store the type of the R.N.G.
Also, we remember the last location, since this is more efficient than
indexing every time to find the address of the last element to see if
the front and rear pointers have wrapped. */
.state = &randtbl[1],
.rand_type = TYPE_3,
.rand_deg = DEG_3,
.rand_sep = SEP_3,
.end_ptr = &randtbl[sizeof (randtbl) / sizeof (randtbl[0])]
};
Bye,
Skybuck.
