On Tue, 2013-05-14 at 08:52 +0200, Martti Kühne wrote:
> Sorry if this is OT and a dumb question, but are you sure you want
>
> On Mon, May 13, 2013 at 8:20 PM, LANGLOIS Olivier PIS -EXT
> <olivier.pis.langlois@xxxxxxxxxxxxxxxxxxxx> wrote:
> [...]
> > struct B
> > {
> > int numelem;
> > /*
> > * Old C trick to define a dynamically sizable array just by allocating
> > * sizeof(B) + (numelem-1)*sizeof(A) memory.
> > */
> > A item[1];
> > };
> >
>
> one item vs.
>
That is a old C trick when STL container did not exist. The other
options would be to replace the 1 item array with pointer but then you
would have to do 2 malloc. 1 for struct B 1 for the array of A.
Maybe my usage of B array did obfuscate the pattern. An another way to
use it is:
B *p = (B *)malloc(sizeof(B) + (numelem-1)*sizeof(A));
That way you can define dynamically the say of the 'item' array. This
pattern dates back way before C99 standard which did, I think, introduce
dynamic array where you could write
B array[var];
