On Wednesday, 8 July 2009 at 22:55:47 UTC, Jarrett Billingsley
wrote:
I noticed in the spec on arrays that "A [fixed-size] array with
a
dimension of 0 is allowed, but no space is allocated for it.
It's
useful as the last member of a variable length struct.." This
sounds
like C99's "flexible array members," where a struct can have an
array
as its last element that isn't given a size, specifically for
allowing
variable-sized structs.
Well, the issue with a zero-length fixed-size array is that..
uh, you
can't access anything out of it. The compiler disallows any
indexing
of a zero-length array with constant indices, and at runtime,
all
accesses caught by the array bounds checking. Weirder still,
the .ptr
of any zero-length array is always null, so you can't even do
things
like "arr.ptr[5] = x;" (which would be perfectly acceptable in
my
opinion).
Just a silly issue.
Just thought I'd mention that this works now, since this is the
only forum thread that mentions working with C's flexible array
members. You simply define a zero-length array and then access
it using .ptr, as in this C binding and example program I
recently translated:
https://github.com/joakim-noah/usrsctp/blob/master/usrsctp.d#L185
https://github.com/joakim-noah/usrsctp/blob/master/programs/rtcweb.d#L836
