+ /* When non-NULL, this is the method called by 'setvbuf' for this port.
+ It must create read and write buffers for PORT with the specified
+ sizes (a size of 0 is for unbuffered ports, which should use the
+ 'shortbuf' field.) Size -1 means to use the port's preferred buffer
+ size. */
+ void (*setvbuf) (SCM port, long read_size, long write_size);
+
+ unsigned flags;