Re: [RFC PATCH] explicitly mark recursion count

[viro@parcelfarce.linux.theplanet.co.uk]

On Wed, Jun 02, 2004 at 09:45:15PM +0200, Jörn Engel wrote:
> On Wed, 2 June 2004 20:37:20 +0100, viro@parcelfarce.linux.theplanet.co.uk wrote:
> > On Wed, Jun 02, 2004 at 08:58:32PM +0200, Jörn Engel wrote:
> > > Note the "in the most general case" part.  You can get things right if
> > > you make some assumptions and those assumptions are actually valid.
> > > In my case the assumptions are:
> > > 1. all relevant function pointers are stuffed into some struct and
> > 
> > Wrong.  They are often passed as arguments to generic helpers, without
> > being ever put into any structures.
> 
> Ok.  Would it be ok to use the following then?
> 
> b1. Function pointer are passed as arguments to functions and
> b2. those pointer are called directly from the function, they are
>     passed to.

Again not guaranteed to be true - they can be (and often are) passed further.

Moreover, they are also stored untyped in structures.  Common pattern
is
	foo.callback = f;
	foo.argument = p;
	iterate_over_blah(blah, &foo);

Note that here f is the only thing that will see the value of p _and_ the
only thing that cares about type of p.  iterator itself doesn't care and
can be used for different types.