Scm_PortErrorClass  128 src/error.c        SCM_CLASS_STATIC_PTR(Scm_PortErrorClass),
Scm_PortErrorClass  147 src/error.c    SCM_DEFINE_BASE_CLASS(Scm_PortErrorClass, ScmPortError,
Scm_PortErrorClass  158 src/gauche/exception.h SCM_CLASS_DECL(Scm_PortErrorClass);
Scm_PortErrorClass  159 src/gauche/exception.h #define SCM_CLASS_PORT_ERROR     (&Scm_PortErrorClass)