.\"	$OpenBSD: bind.2,v 1.22 2021/01/03 18:10:27 rob Exp $
.\"	$NetBSD: bind.2,v 1.8 1995/10/12 15:40:46 jtc Exp $
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.\"     @(#)bind.2	8.1 (Berkeley) 6/4/93
.\"
.Dd $Mdocdate: January 3 2021 $
.Dt BIND 2
.Os
.Sh NAME
.Nm bind
.Nd bind a name to a socket
.Sh SYNOPSIS
.In sys/socket.h
.Ft int
.Fn bind "int s" "const struct sockaddr *name" "socklen_t namelen"
.Sh DESCRIPTION
.Fn bind
assigns a name to an unnamed socket.
When a socket is created with
.Xr socket 2
it exists in a name space (address family) but has no name assigned.
.Fn bind
requests that
.Fa name
be assigned to the socket.
.Fa namelen
indicates the amount of space pointed to by
.Fa name ,
in bytes; the
.Fa sa_len
member of
.Fa name
is ignored.
.Sh NOTES
Binding a name in the
.Ux Ns -domain
creates a socket in the file system that must be deleted by the caller
when it is no longer needed (using
.Xr unlink 2 ) .
.Pp
The rules used in name binding vary between communication domains.
Consult the manual entries in section 4 for detailed information.
.Sh RETURN VALUES
.Rv -std
.Sh ERRORS
The
.Fn bind
function will fail if:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa s
is not a valid descriptor.
.It Bq Er ENOTSOCK
.Fa s
is not a socket.
.It Bq Er EADDRNOTAVAIL
The specified address is not available from the local machine.
.It Bq Er EADDRINUSE
The specified address is already in use.
.It Bq Er EINVAL
The socket is already bound to an address, or
.Fa namelen
is not a valid length for the supplied address.
.It Bq Er EAFNOSUPPORT
The family of the socket and that requested in
.Va name->sa_family
are not equivalent.
.It Bq Er ENOBUFS
Insufficient buffer space is available.
.It Bq Er EACCES
The requested address is protected, and the current user
has inadequate permission to access it.
.It Bq Er EFAULT
The
.Fa name
parameter is not in a valid part of the user address space.
.El
.Pp
The following errors are specific to binding names in the
.Ux Ns -domain .
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded
.Dv NAME_MAX
characters, or an entire pathname (including the terminating NUL)
exceeded
.Dv PATH_MAX
bytes.
.It Bq Er ENOENT
A prefix component of the pathname does not exist.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EIO
An I/O error occurred while making the directory entry or allocating the inode.
.It Bq Er EROFS
The name would reside on a read-only file system.
.It Bq Er EISDIR
An empty pathname was specified.
.El
.Sh SEE ALSO
.Xr connect 2 ,
.Xr getsockname 2 ,
.Xr listen 2 ,
.Xr socket 2
.Sh STANDARDS
The
.Fn bind
function conforms to
.St -p1003.1-2008 .
.Sh HISTORY
The
.Fn bind
system call first appeared in
.Bx 4.1c .