On Wed, Oct 19, 2011 at 10:01:33PM +0100, David Laight wrote:
> > > some dtrace ioctls, including DTRACEIOC_AGGSNAP, are defined as
> > > the following.
> > >
> > > #define DTRACEIOC_AGGSNAP _IOW('x',7,dtrace_bufdesc_t *)
> > >
> > > and libdtrace has diffs like the following.
> > >
> > > #if defined(sun)
> > > if (dt_ioctl(dtp, DTRACEIOC_AGGSNAP, buf) == -1) {
> > > #else
> > > if (dt_ioctl(dtp, DTRACEIOC_AGGSNAP, &buf) == -1) {
> > > #endif
> > >
> > > they seem weird to me.
> > > why can't they be like the following?
> > >
> > > _IOW('x',7,dtrace_bufdesc_t)
> >
> > I don't see any obvious reason... even though dtrace_bufdesc_t is not
> > actually a primitive type, it's only a 40-byte structure, so it should
> > be fine...
>
> Hmmm... the sun code is passing the structure by value
Is it? The non-sun code appears to be calling an ioctl that's defined
to take a pointer to a pointer to a structure. Or maybe I'm totally
misreading ioccom.h?
> - which is
> probably ABI compatible with passing the address of a copy!
yes, I was thinking of that :-/
--
David A. Holland
dholl...@netbsd.org
