Como PD é iniciado?

http://puredata.info/docs/developer/PdStartupOrder

Como PD troca mensagens com TK?

Arquivo m_pd.h:

    /* ------- GUI interface - functions to send strings to TK --------- */
    typedef void (*t_guicallbackfn)(t_gobj *client, t_glist *glist);

    EXTERN void sys_vgui(char *fmt, ...);
    EXTERN void sys_gui(char *s);
    EXTERN void sys_pretendguibytes(int n);
    EXTERN void sys_queuegui(void *client, t_glist *glist, t_guicallbackfn f);
    EXTERN void sys_unqueuegui(void *client);
        /* dialog window creation and destruction */
    EXTERN void gfxstub_new(t_pd *owner, void *key, const char *cmd);
    EXTERN void gfxstub_deleteforkey(void *key);

    extern t_class *glob_pdobject;  /* object to send "pd" messages */

Arquivo s_inter.c, função sys_vgui().