.\" -*- mode: troff; coding: utf-8 -*- .\" Automatically generated by Podwrapper::Man 1.20.0 (Pod::Simple 3.43) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. .ie n \{\ . ds C` "" . ds C' "" 'br\} .el\{\ . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "nbd_aio_opt_set_meta_context_queries 3" .TH nbd_aio_opt_set_meta_context_queries 3 2024-05-31 libnbd-1.20.0 LIBNBD .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH NAME nbd_aio_opt_set_meta_context_queries \- select specific meta contexts, with explicit query list .SH SYNOPSIS .IX Header "SYNOPSIS" .Vb 1 \& #include \& \& typedef struct { \& int (*callback) (void *user_data, const char *name); \& void *user_data; \& void (*free) (void *user_data); \& } nbd_context_callback; \& \& typedef struct { \& int (*callback) (void *user_data, int *error); \& void *user_data; \& void (*free) (void *user_data); \& } nbd_completion_callback; \& \& int nbd_aio_opt_set_meta_context_queries ( \& struct nbd_handle *h, char **queries, \& nbd_context_callback context_callback, \& nbd_completion_callback completion_callback \& ); .Ve .SH DESCRIPTION .IX Header "DESCRIPTION" Request that the server supply all recognized meta contexts passed in through \f(CW\*(C`queries\*(C'\fR, in conjunction with the export previously specified by the most recent \fBnbd_set_export_name\fR\|(3) or \fBnbd_connect_uri\fR\|(3). This can only be used if \fBnbd_set_opt_mode\fR\|(3) enabled option mode. Normally, this function is redundant, as \fBnbd_opt_go\fR\|(3) automatically does the same task if structured replies or extended headers have already been negotiated. But manual control over meta context requests can be useful for fine-grained testing of how a server handles unusual negotiation sequences. Often, use of this function is coupled with \fBnbd_set_request_meta_context\fR\|(3) to bypass the automatic context request normally performed by \&\fBnbd_opt_go\fR\|(3). .PP To determine when the request completes, wait for \&\fBnbd_aio_is_connecting\fR\|(3) to return false. Or supply the optional \&\f(CW\*(C`completion_callback\*(C'\fR which will be invoked as described in "Completion callbacks" in \fBlibnbd\fR\|(3), except that it is automatically retired regardless of return value. Note that detecting whether the server returns an error (as is done by the return value of the synchronous counterpart) is only possible with a completion callback. .SH "RETURN VALUE" .IX Header "RETURN VALUE" This call returns an integer ≥ \f(CW0\fR. .SH ERRORS .IX Header "ERRORS" On error \f(CW\-1\fR is returned. .PP Refer to "ERROR HANDLING" in \fBlibnbd\fR\|(3) for how to get further details of the error. .PP The following parameters must not be NULL: \f(CW\*(C`h\*(C'\fR, \f(CW\*(C`queries\*(C'\fR. For more information see "Non-NULL parameters" in \fBlibnbd\fR\|(3). .SH "HANDLE STATE" .IX Header "HANDLE STATE" nbd_aio_opt_set_meta_context_queries can be called when the handle is in the following state: .PP .Vb 8 \& ┌─────────────────────────────────────┬─────────────────────────┐ \& │ Handle created, before connecting │ ❌ error │ \& │ Connecting │ ❌ error │ \& │ Connecting & handshaking (opt_mode) │ ✅ allowed │ \& │ Connected to the server │ ❌ error │ \& │ Connection shut down │ ❌ error │ \& │ Handle dead │ ❌ error │ \& └─────────────────────────────────────┴─────────────────────────┘ .Ve .SH VERSION .IX Header "VERSION" This function first appeared in libnbd 1.16. .PP If you need to test if this function is available at compile time check if the following macro is defined: .PP .Vb 1 \& #define LIBNBD_HAVE_NBD_AIO_OPT_SET_META_CONTEXT_QUERIES 1 .Ve .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBnbd_aio_is_connecting\fR\|(3), \&\fBnbd_aio_opt_set_meta_context\fR\|(3), \&\fBnbd_connect_uri\fR\|(3), \&\fBnbd_create\fR\|(3), \&\fBnbd_opt_go\fR\|(3), \&\fBnbd_opt_set_meta_context_queries\fR\|(3), \&\fBnbd_set_export_name\fR\|(3), \&\fBnbd_set_opt_mode\fR\|(3), \&\fBnbd_set_request_meta_context\fR\|(3), \&\fBlibnbd\fR\|(3). .SH AUTHORS .IX Header "AUTHORS" Eric Blake .PP Richard W.M. Jones .SH COPYRIGHT .IX Header "COPYRIGHT" Copyright Red Hat .SH LICENSE .IX Header "LICENSE" This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. .PP This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. .PP You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110\-1301 USA