1gensio_set_read_callback_enaLbilber(a3r)y FunctionsgMeannsuiaol_set_read_callback_enable(3)
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NAME

6       gensio_set_read_callback_enable, gensio_set_write_callback_enable - En‐
7       able or disable read data and write ready
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SYNOPSIS

10       #include <gensio/gensio.h>
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12       void gensio_set_read_callback_enable(struct gensio *io,
13                           bool enabled);
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15       void gensio_set_write_callback_enable(struct gensio *io,
16                           bool enabled);
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DESCRIPTION

19       These function enable the write callback, or  the  read  callback,  for
20       gensios (and all child gensios).  Generally disabling the read callback
21       will disable all callbacks except write because it  won't  receive  any
22       data to do any processing.
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24       After  you open a gensio or receive a gensio from an accepter, the gen‐
25       sio has all the enables set to false.  You would generally want to  en‐
26       able the read callback and leave it enabled as much as possible so that
27       low-level processing will happen on the gensio.   In  particular,  dis‐
28       abling read on a UDP gensio will disable all read an accept processing.
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30       Enabling the write callback will enable the callback to tell you if the
31       gensio can currently write any data.  You normally want to  leave  this
32       disabled  and  enable it if you write data and get a partial write.  Or
33       even better, when you have data to write, enable the write callback and
34       write the data from the callback, disabling when it is all written.
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36       Disabling  the write callback does not necessarily keep data from being
37       transmitted by the gensio.  The SSL gensio, for instance, may  transmit
38       key  information on a rekey, or other gensios may transmit flow-control
39       information.  This only affects the write callback.
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41       Disabling the callbacks may not be immediate.  "Immediate" is  hard  to
42       define  in  a  SMP  system,  anyway.  There may be callbacks running or
43       about to be called when you disable the callback, they may  still  run.
44       You must be prepared to handle these race conditions.
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RETURN VALUES

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

50       gensio_err(3), gensio(5)
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54                                  27 Feb 2019gensio_set_read_callback_enable(3)
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