Yop,

I'm trying to learn how to make my first useful externals from scratch. I managed to use a float argument, as in the famous counter example, passing a float argument. But now I'd like to be able to take a symbolic argument, a string of characters (something that I'll use within a sprintf to get a correct formatted string later). A name, basically

It's stupid, but couldn't remember a simple external using only a symbol as argument to get inspired from. Could someone point me to a simple external source that could serve as an example ? I know i will have to put A_DEFSYMBOL in the setup routine, but besides that I'm not finding my way out.

I'll be away from keyboard for 20 days so no matter if you take your time

Thanks

Nau

yep,

just replyingto myself, partially : this site could be useful : http://www.ime.usp.br/~fls/PDExternal-generator/PDExternal_generator.html

Cheers

Nau

Back here,

still can't find a way to handle a symbol argument. I'm a total noob in C, so I try to find my way step by step, and I'm stuck with something like a type mismatch I can't resolve with my poor means. Sorry for beeing so noob.

Basically I'd like to get a string of caracters as unique argument and use it to create a filename with a sprintf.

I illustrate my problem with two externals, the first one uses a floatarg and works fine, the second tries to the content of the symbol argument but fails. (compiled on a cubieboard2 (armf)).
arguse.tar.bz2

Anyone knows what to do here ?

Sorry again for the noobness,
Thank you,

Nau

In the source code of [filter~] from iemlib, you get this line in the new method:
filt_typ = atom_getsymbolarg(0, argc, argv);

This gets a string passed as an argument when you create the object. Can't you use this technique?

I'll try, for sure.

Thank you !

Nau

when A_GIMME is used as the argument to the constructor the method alexandros proposes should work well.
However, you can also use A_DEFSYMBOL as you were doing. I think maybe your problem was that you were thinking that a symbol was a char *, which is not the case. the definition of t_symbol is in m_pd.h, and the actual array of characters is in t_symbol.s_name.
At any rate, here's the corrected .c file:arguse2.c

Thank you Sebfumaster, that was exactly what I needed.

Nau