int off = ps->start_location_.start () - sf->c_str ();
- scm_seek (port, scm_long2num (off), scm_long2num (SEEK_SET));
+ scm_seek (port, scm_from_long (off), scm_from_long (SEEK_SET));
SCM from = scm_ftell (port);
scm_set_port_line_x (port, scm_from_int (ps->start_location_.line_number () -1));