[PD] How to implement an @ argument in an external object?

[Alexandros]

Thanks a lot for the explanation, it worked!


On 02/08/2018 09:15 μμ, Claude Heiland-Allen wrote:
> Hi Alexandros
>
> You can compare symbols for string equality by pointer equality
> (because symbols are interned in a table and never released - fast
> equality check is the whole point of symbols in Pd).
>
> Something like this (untested):
>
> static t_symbol *s_at_sync = 0;
> extern void foo_setup(void)
> {
>   s_at_sync = gensym("@sync");
>   ...
> }
>
> void *foo_new(int argc, t_atom *argv)
> {
>   if (atom_getsym(argv[3]) == s_at_sync)
>   {
>      sync();
>   }
>   ...
> }
>
> Or you can get the pointer to the symbol's string from the symbol
> struct, see m_pd.h for details.  You must not modify the string, but
> you could access it to see if it starts with '@' for example.
>
>
> Claude
>
> On 02/08/18 21:02, Alexandros wrote:
>>
>> Coming back to this thread after some time.
>>
>> I'm trying to check whether a given argument to an external I'm
>> writing starts with "@" or if it is actually "@sync", but can't seem
>> to make it work. Can't really understand how t_symbol works. I'm
>> iterating though the arguments with int argc and t_atom *argv and if
>> there are the right number of arguments, I'm retrieving the argument
>> that's supposed to be "@sync" with atom_gensym(argv);
>>
>> I don't know how to compare that to a hard-coded string, like "@", or
>> "@sync". I tried comparing straight to these strings, tried strcmp(),
>> but I don't know how to do this, and couldn't find examples online.
>>
>> Any hints?
>>
>>
>> On 26/02/2018 07:36 μμ, IOhannes m zmölnig wrote:
>>> On 02/26/2018 08:09 PM, Alexandros wrote:
>>>> Being informed about the mailing list archive correct link, I searched
>>>> for messages about this but didn't find something (it's possible I've
>>>> missed something though).
>>>>
>>>> I'm writing an external and I want to use an @ argument (for example
>>>> "@sync hard"). How does one implement this in C code?
>>>>
>>> either use flext (but then you write C++) and it comes for free.
>>>
>>> or simply iterate over the arguments, looking for symbols starting with
>>> "@" (or simply search for symbols that are "@sync"), then check whether
>>> there's another argument after that and see which value it has.
>>>
>>> fgdamrs
>>> IOhannes
>>>
>>>
>>>
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>>
>>
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