NAME

       gensio_set_read_callback_enable, gensio_set_write_callback_enable - Enable or disable read
       data and write ready

SYNOPSIS

       #include <gensio/gensio.h>

       void gensio_set_read_callback_enable(struct gensio *io,
                           bool enabled);

       void gensio_set_write_callback_enable(struct gensio *io,
                           bool enabled);

DESCRIPTION

       These function enable the write callback, or the read callback, for gensios (and all child
       gensios).   Generally  disabling the read callback will disable all callbacks except write
       because it won't receive any data to do any processing.

       After you open a gensio or receive a gensio from an  accepter,  the  gensio  has  all  the
       enables  set  to false.  You would generally want to enable the read callback and leave it
       enabled as much as possible so that low-level processing will happen on  the  gensio.   In
       particular, disabling read on a UDP gensio will disable all read an accept processing.

       Enabling  the  write  callback  will  enable  the  callback  to tell you if the gensio can
       currently write any data.  You normally want to leave this disabled and enable it  if  you
       write  data  and get a partial write.  Or even better, when you have data to write, enable
       the write callback and write the data from the callback, disabling when it is all written.

       Disabling the write callback does not necessarily keep data from being transmitted by  the
       gensio.   The  SSL gensio, for instance, may transmit key information on a rekey, or other
       gensios may transmit flow-control information.  This only affects the write callback.

       Disabling the callbacks may not be immediate.  "Immediate" is hard  to  define  in  a  SMP
       system, anyway.  There may be callbacks running or about to be called when you disable the
       callback, they may still run.  You must be prepared to handle these race conditions.

RETURN VALUES

       Zero is returned on success, or a gensio error on failure.

SEE ALSO

       gensio_err(3), gensio(5)

                                           27 Feb 2019         gensio_set_read_callback_enable(3)