- SCM proc = ly_scheme_function ("percussion?");
-
- SCM drums = scm_call_1 (proc, ly_symbol2scm (instrument_string_.to_str0 ()));
- audio_staff_->channel_ = (drums == SCM_BOOL_T ? 9 : -1 );
+ SCM proc = ly_lily_module_constant ("percussion?");
+
+ SCM drums = scm_call_1 (proc, ly_symbol2scm (instrument_string_.c_str ()));
+ audio_staff_->channel_ = (drums == SCM_BOOL_T ? 9 : -1);