Re: Global constants

[Mark McLoughlin <markmc at redhat dot com>]

Hi,

On Mon, 2006-02-13 at 15:10 -0500, Frank Ch. Eigler wrote:

> > Also it would be nice to have a way to declare these constants in
> > embedded C [...]
> > something like
> > %{ const_O_CREAT = O_CREAT; %}
> >   instead of
> > O_CREAT = 64
> 
> One problem with this is that globals, if elided by the optimizer,
> would still have such references within the opaque embedded-C blocks.
> (That's one of the reasons that embedded-C code should not refer to
> systemtap data other than its arguments.)

	Yep, that's why I initially was doing this:

	In translate.cxx:emit_global()

    ---
       o->newline() << "static rwlock_t "
                    << "global_" << c_varname (v->name) << "_lock;";
    +  o->newline() << "#define global_"
    +               << c_varname(v->name) << "_DEFINED 1";
    ---

	and then

    ---
    global O_CREAT

    function init_sys_open_flags () %{
    #ifdef global_O_CREAT_DEFINED
        global_O_CREAT = 64;
    #endif
    %}
    ---

Cheers,
Mark.