moin Alain,
I've never passed pointers around between externals myself, but...
On 2007-06-22 04:57:35, <[EMAIL PROTECTED]> appears to have written:
> I am trying to send some data out of an outlet using a symbol pointer. I have
> tried using sprintf like
> martin suggested with little succes. I am sure I am the one doing something
> wrong. I am getting a
> pointer symbol but I am not able to convert the pointer back. In external#1
> I have:
>
> The out ----------------
> IplImage *frame;
> char symstr[10];
> t_symbol *sym;
> sprintf(symstr, "%p", frame);
> sym = gensym(symstr);
> outlet_symbol(x->m_outFrames, sym);
>
> With this I get an address like:
> symbol 0x1159da0
... looks kosher to me ...
> ...but on the conversion in external#2 I get the problem. The conversion
> looks like:
>
> The in-----------------------
> IplImage *in_frame;
> x->in_frame = (IplImage *)atol(s->s_name);
> post("frame %s", x->in_frame);
> post("symbol %s",s->s_name);
>
> ...with this I get this:
> frame (null)
> symbol 0x1159da0
first of all, you probably want to post("frame %p", x->in_frame), rather
than "%s". Second, in the docs for my atol (here under linux|glibc), I see:
-- Function: long int atol (const char *STRING)
This function is similar to the `strtol' function with a BASE
argument of `10', except that it need not detect overflow errors.
The `atol' function is provided mostly for compatibility with
existing code; using `strtol' is more robust.
... so if your atol() is similar, then trying to convert a hex string to
a pointer with atol() is an exercise in futility (since in general,
10!=16). strtol() ought to work better, auto-detetcting the hex-iness
of the string by its '0x' prefix. You might also just want to roll out
the big guns and use the "%x" format to scanf(), but strtol() is likely
to be the better way to go.
marmosets,
Bryan
--
Bryan Jurish "There is *always* one more bug."
[EMAIL PROTECTED] -Lubarsky's Law of Cybernetic Entomology
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