=head1 NAME

nbd_get_nr_meta_contexts - return the current number of requested meta
contexts

=head1 SYNOPSIS

 #include <libnbd.h>

 ssize_t nbd_get_nr_meta_contexts (
           struct nbd_handle *h
         );

=head1 DESCRIPTION

During connection libnbd can negotiate zero or more metadata
contexts with the server.  Metadata contexts are features (such
as C<"base:allocation">) which describe information returned
by the L<nbd_block_status_64(3)> command (for C<"base:allocation">
this is whether blocks of data are allocated, zero or sparse).

This command returns how many meta contexts have been added to
the list to request from the server via L<nbd_add_meta_context(3)>.
The server is not obligated to honor all of the requests; to see
what it actually supports, see L<nbd_can_meta_context(3)>.

=head1 RETURN VALUE

This call returns an integer size E<ge> 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 VERSION

This function first appeared in libnbd 1.6.

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

 #define LIBNBD_HAVE_NBD_GET_NR_META_CONTEXTS 1

=head1 SEE ALSO

L<nbd_add_meta_context(3)>,
L<nbd_block_status_64(3)>,
L<nbd_can_meta_context(3)>,
L<nbd_clear_meta_contexts(3)>,
L<nbd_create(3)>,
L<nbd_get_meta_context(3)>,
L<libnbd(3)>.

=head1 AUTHORS

Eric Blake

Richard W.M. Jones

=head1 COPYRIGHT

Copyright Red Hat
