dtrace discuss - Jun 2009 - (dtrace error) "operator -> cannot be applied to a forward declaration ..."

Hi,

This may be more suited to a general D mailing list, but - i''m trying
to analyse LWP activity on a system, and faltering at the first hurdle. The
lwp_create() call is prototyped as:

klwp_t * lwp_create(void (*proc)(), caddr_t arg, size_t len, proc_t *p, int
state, int pri, const k_sigset_t *smask, int cid, id_t lwpid)

This is currently the only call i''m probing, but I am having trouble
accessing the proc_t structure; specifically it''s members, such as
p_ppid for instance.

The error I am getting is:

"operator -> cannot be applied to a forward declaration: no struct
proc_t definition is available"

.. and the code I have so far is:

fbt:genunix:lwp_create:entry
{
self->ppid = ((struct proc_t *)arg3)->p_ppid;
}

Can anyone kindly shed some light on the errors with the cast please?

Cheers

Dan.
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This message posted from opensolaris.org

Hi,

This may be more suited to a general D mailing list, but - i''m trying
to analyse LWP activity on a system, and faltering at the first hurdle. The
lwp_create() call is prototyped as:

klwp_t * lwp_create(void (*proc)(), caddr_t arg, size_t len, proc_t *p, int
state, int pri, const k_sigset_t *smask, int cid, id_t lwpid)

This is currently the only call i''m probing, but I am having trouble
accessing the proc_t structure; specifically it''s members, such as
p_ppid for instance.

The error I am getting is:

"operator -> cannot be applied to a forward declaration: no struct
proc_t definition is available"

.. and the code I have so far is:

fbt:genunix:lwp_create:entry
{
self->ppid = ((struct proc_t *)arg3)->p_ppid;
}

Can anyone kindly shed some light on the errors with the cast please?

Cheers

Dan.
-- 
This message posted from opensolaris.org

> The error I am getting is:
>
> "operator -> cannot be applied to a forward declaration: no struct
> proc_t definition is available"

You need to use the same syntax as in C. This means either
''proc_t'' or
''struct proc''.

Adam

--
Adam Leventhal, Fishworks                        http://blogs.sun.com/ahl

On Fri, Jun 5, 2009 at 9:48 AM, Danny Webster<dannywebster at gmail.com>
wrote:
> Hi,
>
> This may be more suited to a general D mailing list, but - i''m
trying to analyse LWP activity on a system, and faltering at the first hurdle.
The lwp_create() call is prototyped as:
>
> klwp_t * lwp_create(void (*proc)(), caddr_t arg, size_t len, proc_t *p, int
state, int pri, const k_sigset_t *smask, int cid, id_t lwpid)
>
> This is currently the only call i''m probing, but I am having
trouble accessing the proc_t structure; specifically it''s members, such
as p_ppid for instance.
>
> The error I am getting is:
>
> "operator -> cannot be applied to a forward declaration: no struct
proc_t definition is available"
>
> .. and the code I have so far is:
>
> fbt:genunix:lwp_create:entry
> {
> self->ppid = ((struct proc_t *)arg3)->p_ppid;
> }
>
> Can anyone kindly shed some light on the errors with the cast please?
It looks like the type of the argument is "proc_t *" and not
"struct proc_t *".

You might also try "args[3]", which gives you the typed argument.

Chad

Chad Mynhier replied to this - his suggestion was to use drop the
"struct" from "struct proc_t *", which fixed the issue.

Thanks Chad!
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