=head1 NAME

nbd_connect_socket - connect directly to a connected socket

=head1 SYNOPSIS

 #include <libnbd.h>

 int nbd_connect_socket (
       struct nbd_handle *h, int sock
     );

=head1 DESCRIPTION

Pass a connected socket C<sock> through which libnbd will talk
to the NBD server.

The caller is responsible for creating and connecting this
socket by some method, before passing it to libnbd.

If this call returns without error then socket ownership
is passed to libnbd.  Libnbd will close the socket when the
handle is closed.  The caller must not use the socket in any way.


This call returns when the connection has been made.  By default,
this proceeds all the way to transmission phase, but
L<nbd_set_opt_mode(3)> can be used for manual control over
option negotiation performed before transmission phase.

=head1 RETURN VALUE

If the call is successful the function returns C<0>.

=head1 ERRORS

On error C<-1> is returned.

Refer to L<libnbd(3)/ERROR HANDLING>
for how to get further details of the error.

The following parameters must not be NULL: C<h>.
For more information see L<libnbd(3)/Non-NULL parameters>.

=head1 HANDLE STATE

nbd_connect_socket
can be called when the handle is in the following state:

 ┌─────────────────────────────────────┬─────────────────────────┐
 │ Handle created, before connecting   │ ✅ allowed              │
 │ Connecting                          │ ❌ error                │
 │ Connecting & handshaking (opt_mode) │ ❌ error                │
 │ Connected to the server             │ ❌ error                │
 │ Connection shut down                │ ❌ error                │
 │ Handle dead                         │ ❌ error                │
 └─────────────────────────────────────┴─────────────────────────┘

=head1 VERSION

This function first appeared in libnbd 1.2.

If you need to test if this function is available at compile time
check if the following macro is defined:

 #define LIBNBD_HAVE_NBD_CONNECT_SOCKET 1

=head1 SEE ALSO

L<nbd_aio_connect_socket(3)>,
L<nbd_connect_command(3)>,
L<nbd_create(3)>,
L<nbd_set_opt_mode(3)>,
L<libnbd(3)>,
L<socket(7)>.

=head1 AUTHORS

Eric Blake

Richard W.M. Jones

=head1 COPYRIGHT

Copyright Red Hat
