244 lines
6.3 KiB
Groff
244 lines
6.3 KiB
Groff
.\" $NetBSD: sockaddr_snprintf.3,v 1.5 2005/04/13 23:08:03 wiz Exp $
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.\"
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.\" Copyright (c) 2004 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Christos Zoulas.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd April 9, 2005
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.Dt SOCKADDR_SNPRINTF 3
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.Os
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.Sh NAME
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.Nm sockaddr_snprintf
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.Nd formatting function for socket address structures
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.Sh LIBRARY
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.Lb libutil
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.Sh SYNOPSIS
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.In util.h
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.Ft int
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.Fn sockaddr_snprintf "char *buf" "size_t buflen" "const char *fmt" "const struct sockaddr *sa"
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.Sh DESCRIPTION
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The
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.Fn sockaddr_snprintf
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function formats a socket address into a form suitable for printing.
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.Pp
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This function is convenient because it is protocol independent, i.e. one does
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not need to know the address family of the sockaddr in order to print it.
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The
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.Xr printf 3
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like format string specifies how the address is going to be printed.
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Some formatting characters are only supported by some address families.
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If a certain formatting character is not supported, then the string
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.Dq N/A
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is printed.
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.Pp
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The resulting formatted string is placed into
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.Fa buf .
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Up to
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.Fa buflen
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characters are placed in
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.Fa buf .
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.Pp
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The following formatting characters are supported (immediately
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after a percent
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.Pq Sq %
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sign):
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.Bl -tag -width %a
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.It a
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The node address portion of the socket address is printed numerically.
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For
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.Dv AF_INET
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the address is printed as:
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.Dq A.B.C.D
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and
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for AF_INET6
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the address is printed as:
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.Dq A:B...[%if]
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using
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.Xr getnameinfo 3
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internally with
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.Dv NI_NUMERICHOST .
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For
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.Dv AF_APPLETALK
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the address is printed as:
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.Dq A.B
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For
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.Dv AF_LOCAL
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.Pq Dv AF_UNIX
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the address is printed as:
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.Dq socket-path
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For
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.Dv AF_LINK
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the address is printed as:
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.Dq a.b.c.d.e.f
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using
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.Xr link_ntoa 3 ,
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but the interface portion is skipped (see below).
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For
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.Dv AF_UNSPEC
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nothing is printed.
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.It A
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The symbolic name of the address is printed.
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For
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.Dv AF_INET
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and
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.AF_INET6
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this is the hostname associated with the address.
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For all other address families, it is the same as the
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.Dq a
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format.
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.It f
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The numeric value of the family of the address is printed.
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.It l
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The length of the socket address is printed.
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.It p
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For
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.Dv AF_INET ,
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.Dv AF_INET6 ,
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and
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.Dv AF_APPLETALK
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the numeric value of the port portion of the address is printed.
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.It P
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For
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.Dv AF_INET
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and
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.Dv AF_INET6
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this is the name of the service associated with the port number, if
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available.
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For all other address families, it is the same as the
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.Dq p
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format.
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.It I
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For
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.Dv AF_LINK
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addresses, the interface name portion is printed.
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.It F
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For
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.Dv AF_INET6
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addresses, the flowinfo portion of the address is printed numerically.
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.It R
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For
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.Dv AF_APPLETALK
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addresses, the netrange portion of the address is printed as:
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.Dq phase:[firstnet,lastnet]
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.It S
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For
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.Dv AF_INET6
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addresses, the scope portion of the address is printed numerically.
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.It ?
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If present between
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.Dq %
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and the format character, and the selected format does not apply to
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the given address family, the
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.Dq N/A
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string is elided and no output results.
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.El
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.Sh RETURN VALUES
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The
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.Fn sockaddr_snprintf
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function returns the number of characters that are required to format the
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value
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.Fa val
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given the format string
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.Fa fmt
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excluding the terminating NUL.
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The returned string in
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.Fa buf
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is always NUL-terminated.
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If the address family is not supported,
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.Fn sockaddr_snprintf
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returns \-1 and sets
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.Va errno
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to
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.Dv EAFNOSUPPORT .
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For
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.Dv AF_INET
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and
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.DV AF_INET6
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addresses
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.Fn sockaddr_snprintf
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returns \-1 if the
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.Xr getnameinfo 3
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conversion failed, and
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.Fa errno
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is set to the error value from
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.Xr getnameinfo 3 .
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.Sh ERRORS
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If the buffer
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.Fa buf
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is too small to hold the formatted output,
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.Fn sockaddr_snprintf
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will still return the buffer, containing a truncated string.
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.Sh SEE ALSO
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.Xr getaddrinfo 3 ,
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.Xr getnameinfo 3 ,
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.Xr link_ntoa 3 ,
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.Xr snprintf 3
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.Sh HISTORY
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The
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.Fn sockaddr_snprintf
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first appeared in
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.Nx 3.0 .
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.Sh BUGS
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The
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.Fn sockaddr_snprintf
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interface is experimental and might change in the future.
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.Pp
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There is no way to specify different formatting styles for particular
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addresses.
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For example it would be useful to print
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.Dv AF_LINK
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addresses as
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.Dq %.2x:%.2x...
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instead of
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.Dq %x.%x...
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.Pp
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This function is supposed to be quick, but
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.Xr getnameinfo 3
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might use system calls to convert the scope number to an interface
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name and the
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.Dq A
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and
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.Dq P
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format characters call
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.Xr getaddrinfo 3
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which may block for a noticeable period of time.
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.Pp
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Not all formatting characters are supported by all address families and
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printing
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.Dq N/A
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is not very convenient.
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The
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.Dq \&?
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character can suppress this, but other formatting (e.g., spacing or
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punctuation) will remain.
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