/* Courtesy functions. */
extern valerie_error_code valerie_execute( valerie, size_t, const char *, ... );
-extern valerie_error_code valerie_push( valerie, mlt_service, size_t, char *, ... );
+extern valerie_error_code valerie_push( valerie, mlt_service, size_t, const char *, ... );
/* Close function. */
extern void valerie_close( valerie );