NAME

       gensio_close,  gensio_close_s,  gensio_disable,  gensio_free  - Stop/free a gensio that is
       open

SYNOPSIS

       #include <gensio/gensio.h>

       typedef void (*gensio_done)(struct gensio *io, void *close_data);

       int gensio_close(struct gensio *io, gensio_done close_done,
                           void *close_data);

       int gensio_close_s(struct gensio *io);

       void gensio_disable(struct gensio *io);

       void gensio_free(struct gensio *io);

       gensio_close closes an open gensio.  Note that the close operation is not  complete  until
       close_done()  is called.  This shuts down internal file descriptors and such, but does not
       free the gensio.  If the gensio is a connecting one, you can generally re-open it.  If you
       gensio_close before an open done is reported, the results (primarily whether the open done
       is called) are undefined.  If the open done is called, it will be called before the  close
       done.

       gensio_close_s  is like gensio_close, but blocks until the operation is complete.  BE VERY
       CAREFUL WITH THIS FUNCTION.  Do not call it from a callback because  it  waits  until  all
       operations on the gensio are done, and they won't be done until the callback returns.  You
       will deadlock if you do this.

       gensio_disable disables operation of the gensio so that closing will  not  result  in  any
       data  being  transmitted.   THIS  IS  FOR EXTREMELY LIMITED USE.  This will not close file
       descriptors nor disable I/O, necessarily, but will put the gensio stack into a state where
       freeing  will  not  result in any transmission of data to the other end.  You MUST be in a
       state where no callbacks are running or can run.  This is primarily to allow  a  close  of
       something  like an SSL connection after a fork.  If you didn't have this, the normal close
       in the one fork would shut down the SSL connection for the other fork, too.  See gensio(5)
       for details on forking.

       gensio_free  frees  data associated with the gensio.  If it is open, the gensio is closed.
       If you call gensio_free after gensio_close  before  the  close_done  callback  is  called,
       whether close_done is called is undefined.

RETURN VALUES

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

SEE ALSO

       gensio_err(3), gensio(5)

                                           27 Feb 2019                            gensio_close(3)