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=head1 NAME
nbd_set_request_meta_context - control whether connect automatically
requests meta contexts
=head1 SYNOPSIS
#include <libnbd.h>
int nbd_set_request_meta_context (
struct nbd_handle *h, bool request
);
=head1 DESCRIPTION
This function controls whether the act of
connecting to an export
(all C<nbd_connect_*> calls when L<nbd_set_opt_mode(3)> is false,
or L<nbd_opt_go(3)> and L<nbd_opt_info(3)> when option mode is
enabled) will also try to issue NBD_OPT_SET_META_CONTEXT when
the server supports structured replies or extended headers and
any contexts were registered by L<nbd_add_meta_context(3)>. The
default setting is true; however the extra step of negotiating
meta contexts is not always desirable: performing both info and
go on the same export works without needing to re-negotiate
contexts on the second call; integration testing of other servers
may benefit from manual invocation of L<nbd_opt_set_meta_context(3)>
at other times in the negotiation sequence; and even when using
just L<nbd_opt_info(3)>, it can be faster to collect the server's
results by relying on the callback function passed to
L<nbd_opt_list_meta_context(3)> than a series of post-process
calls to L<nbd_can_meta_context(3)>.
Note that this control has no effect if the server does not
negotiate structured replies or extended headers, or if the
client did not request any contexts via L<nbd_add_meta_context(3)>.
Setting this control to false may cause L<nbd_block_status(3)>
to fail.
=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_set_request_meta_context
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 1.16.
If you need to test if this function is available at compile time
check if the following macro is defined:
#define LIBNBD_HAVE_NBD_SET_REQUEST_META_CONTEXT 1
=head1 SEE ALSO
L<nbd_add_meta_context(3)>,
L<nbd_block_status(3)>,
L<nbd_can_meta_context(3)>,
L<nbd_create(3)>,
L<nbd_get_request_meta_context(3)>,
L<nbd_get_structured_replies_negotiated(3)>,
L<nbd_opt_go(3)>,
L<nbd_opt_info(3)>,
L<nbd_opt_list_meta_context(3)>,
L<nbd_opt_set_meta_context(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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