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=head1 NAME
nbd_clear_meta_contexts - reset the list of requested meta contexts
=head1 SYNOPSIS
#include <libnbd.h>
int nbd_clear_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 resets the list of meta contexts to request back to
an empty list, for re-population by further use of
L<nbd_add_meta_context(3)>. It is primarily useful when option
negotiation mode is selected (see L<nbd_set_opt_mode(3)>), for
altering the list of attempted contexts between subsequent export
queries.
=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_clear_meta_contexts
can be called when the handle is in the following states:
┌─────────────────────────────────────┬─────────────────────────┐
│ Handle created, before connecting │ ✅ allowed │
│ Connecting │ ❌ error │
│ Connecting & handshaking (opt_mode) │ ✅ allowed │
│ Connected to the server │ ❌ error │
│ Connection shut down │ ❌ error │
│ Handle dead │ ❌ error │
└─────────────────────────────────────┴─────────────────────────┘
=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_CLEAR_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_create(3)>,
L<nbd_get_meta_context(3)>,
L<nbd_get_nr_meta_contexts(3)>,
L<nbd_set_opt_mode(3)>,
L<libnbd(3)>.
=head1 AUTHORS
Eric Blake
Richard W.M. Jones
=head1 COPYRIGHT
Copyright Red Hat
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