.TH gensio_open 3 "27 Feb 2019"
.SH NAME
gensio_open, gensio_open_s, gensio_open_nochild, gensio_open_nochild_s
\- Start a connecting gensio
.SH SYNOPSIS
.B #include <gensio/gensio.h>
.TP 20
.B typedef void (*gensio_done_err)(struct gensio *io, int err,
.br
.B                                 void *open_data);
.TP 20
.B int gensio_open(struct gensio *io, gensio_done_err open_done,
.br
.B                 void *open_data);
.TP 20
.B int gensio_open_s(struct gensio *io);
.TP 20
.B int gensio_open_nochild(struct gensio *io, gensio_done_err open_done,
.br
.B                         void *open_data);
.TP 20
int gensio_open_nochild_s(struct gensio *io);
.SH "DESCRIPTION"
.B gensio_open
starts the gensio.  gensios received from an accepter are
open upon receipt, but connecting gensios are started closed and need
to be opened before use.  If no error is returned, the
.I open_done
callback will be called, if there is no error in the callback
.I err
value the gensio will be open.  This will open all children, too.

Note that the
.B open_done
callback will always be called even if you close the gensio before the
.B open_done
callback happens or if an error occurs.  This is guaranteed.

.B gensio_open_s
is like
.B gensio_open, but waits for the open to complete.  Normal gensio
processing will happen while waiting.  Note that you must be careful
to not call this from a callback, you should only call this from a
non-callback thread or a runner (see gensio_os_funcs(3) for details on
runners).

.B gensio_open_nochild
is like
.B gensio_open,
but assumes any child gensios are already open and just opens this
gensio.  This can be useful if you have a gensio that is already
opened (like you received it from an accepter) and you want to stack
another gensio on top of it.  Only filter gensios will support this.

.B gensio_open_nochild_s
is like
.B gensio_open_nochild,
but waits for the open to complete.  See the notes on
.B gensio_open_s
above for warnings.
.SH "RETURN VALUES"
Zero is returned on success, or a gensio error on failure.
.SH "SEE ALSO"
gensio_err(3), gensio(5), gensio_os_funcs(3)