[PD-dev] sending data out using sprintf

[Martin Peach]

nosehair911 at bellsouth.net wrote:
> 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
>
> ...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
>
> So I'm getting the symbol in, but its not converting into "in_fame."
> Does anyone know what I am doing wrong or a way to use Pd's A_POINTER.  I have looked at
> Gem and pdp but I cant figure it out.
>   
Oh yes, atol only converts base 10 but the pointer is in base 16 format. 
Maybe try:
x->in_frame = (IplImage *)sscanf(s->s_name, "%p");
or:
x->in_frame = (IplImage *)sscanf(s->s_name, "%x");

OTOH if you did
sprintf(symstr, "%lu", frame);

first, then atol would probably work OK.

Martin