gistfile1.h

static VALUE
rb_callcc(self)
    VALUE self;
{
    volatile VALUE cont;
    rb_thread_t th;
    volatile rb_thread_t th_save;
    struct tag *tag;
    struct RVarmap *vars;

    THREAD_ALLOC(th);
    cont = Data_Wrap_Struct(rb_cCont, thread_mark, thread_free, th);

    scope_dup(ruby_scope);
    for (tag=prot_tag; tag; tag=tag->prev) {
	scope_dup(tag->scope);
    }
    th->thread = curr_thread->thread;
    th->thgroup = cont_protect;

    for (vars = ruby_dyna_vars; vars; vars = vars->next) {
	if (FL_TEST(vars, DVAR_DONT_RECYCLE)) break;
	FL_SET(vars, DVAR_DONT_RECYCLE);
    }
    th_save = th;
    if (THREAD_SAVE_CONTEXT(th)) {
	return th_save->result;
    }
    else {
	return rb_yield(cont);
    }
}