bind.3p (7394B)
- '\" et
- .TH BIND "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
- .\"
- .SH PROLOG
- This manual page is part of the POSIX Programmer's Manual.
- The Linux implementation of this interface may differ (consult
- the corresponding Linux manual page for details of Linux behavior),
- or the interface may not be implemented on Linux.
- .\"
- .SH NAME
- bind
- \(em bind a name to a socket
- .SH SYNOPSIS
- .LP
- .nf
- #include <sys/socket.h>
- .P
- int bind(int \fIsocket\fP, const struct sockaddr *\fIaddress\fP,
- socklen_t \fIaddress_len\fP);
- .fi
- .SH DESCRIPTION
- The
- \fIbind\fR()
- function shall assign a local socket address
- .IR address
- to a socket identified by descriptor
- .IR socket
- that has no local socket address assigned. Sockets created with the
- \fIsocket\fR()
- function are initially unnamed; they are identified only by their
- address family.
- .P
- The
- \fIbind\fR()
- function takes the following arguments:
- .IP "\fIsocket\fR" 12
- Specifies the file descriptor of the socket to be bound.
- .IP "\fIaddress\fR" 12
- Points to a
- .BR sockaddr
- structure containing the address to be bound to the socket. The length
- and format of the address depend on the address family of the socket.
- .IP "\fIaddress_len\fR" 12
- Specifies the length of the
- .BR sockaddr
- structure pointed to by the
- .IR address
- argument.
- .P
- The socket specified by
- .IR socket
- may require the process to have appropriate privileges to use the
- \fIbind\fR()
- function.
- .P
- If the address family of the socket is AF_UNIX and the pathname in
- .IR address
- names a symbolic link,
- \fIbind\fR()
- shall fail and set
- .IR errno
- to
- .BR [EADDRINUSE] .
- .P
- If the socket address cannot be assigned immediately and O_NONBLOCK is
- set for the file descriptor for the socket,
- \fIbind\fR()
- shall fail and set
- .IR errno
- to
- .BR [EINPROGRESS] ,
- but the assignment request shall not be aborted, and the assignment
- shall be completed asynchronously. Subsequent calls to
- \fIbind\fR()
- for the same socket, before the assignment is completed, shall fail
- and set
- .IR errno
- to
- .BR [EALREADY] .
- .P
- When the assignment has been performed asynchronously,
- \fIpselect\fR(),
- \fIselect\fR(),
- and
- \fIpoll\fR()
- shall indicate that the file descriptor for the socket is ready for
- reading and writing.
- .SH "RETURN VALUE"
- Upon successful completion,
- \fIbind\fR()
- shall return 0; otherwise, \-1 shall be returned and
- .IR errno
- set to indicate the error.
- .SH ERRORS
- The
- \fIbind\fR()
- function shall fail if:
- .TP
- .BR EADDRINUSE
- The specified address is already in use.
- .TP
- .BR EADDRNOTAVAIL
- .br
- The specified address is not available from the local machine.
- .TP
- .BR EAFNOSUPPORT
- .br
- The specified address is not a valid address for the address family of
- the specified socket.
- .TP
- .BR EALREADY
- An assignment request is already in progress for the specified socket.
- .TP
- .BR EBADF
- The
- .IR socket
- argument is not a valid file descriptor.
- .TP
- .BR EINPROGRESS
- O_NONBLOCK is set for the file descriptor for the socket and the
- assignment cannot be immediately performed; the assignment shall be
- performed asynchronously.
- .TP
- .BR EINVAL
- The socket is already bound to an address, and the protocol does not
- support binding to a new address; or the socket has been shut down.
- .TP
- .BR ENOBUFS
- Insufficient resources were available to complete the call.
- .TP
- .BR ENOTSOCK
- The
- .IR socket
- argument does not refer to a socket.
- .TP
- .BR EOPNOTSUPP
- The socket type of the specified socket does not support binding to an
- address.
- .P
- If the address family of the socket is AF_UNIX, then
- \fIbind\fR()
- shall fail if:
- .TP
- .BR EACCES
- A component of the path prefix denies search permission, or the
- requested name requires writing in a directory with a mode that denies
- write permission.
- .TP
- .BR EDESTADDRREQ " or " EISDIR
- .br
- The
- .IR address
- argument is a null pointer.
- .TP
- .BR EIO
- An I/O error occurred.
- .TP
- .BR ELOOP
- A loop exists in symbolic links encountered during resolution of the
- pathname in
- .IR address .
- .TP
- .BR ENAMETOOLONG
- .br
- The length of a component of a pathname is longer than
- {NAME_MAX}.
- .TP
- .BR ENOENT
- A component of the path prefix of the pathname in
- .IR address
- does not name an existing file or the pathname is an empty string.
- .TP
- .BR ENOENT " or " ENOTDIR
- .br
- The pathname in
- .IR address
- contains at least one non-\c
- <slash>
- character and ends with one or more trailing
- <slash>
- characters. If the pathname without the trailing
- <slash>
- characters would name an existing file, an
- .BR [ENOENT]
- error shall not occur.
- .TP
- .BR ENOTDIR
- A component of the path prefix of the pathname in
- .IR address
- names an existing file that is neither a directory nor a symbolic link
- to a directory, or the pathname in
- .IR address
- contains at least one non-\c
- <slash>
- character and ends with one or more trailing
- <slash>
- characters and the last pathname component names an existing file
- that is neither a directory nor a symbolic link to a directory.
- .TP
- .BR EROFS
- The name would reside on a read-only file system.
- .P
- The
- \fIbind\fR()
- function may fail if:
- .TP
- .BR EACCES
- The specified address is protected and the current user does not have
- permission to bind to it.
- .TP
- .BR EINVAL
- The
- .IR address_len
- argument is not a valid length for the address family.
- .TP
- .BR EISCONN
- The socket is already connected.
- .TP
- .BR ELOOP
- More than
- {SYMLOOP_MAX}
- symbolic links were encountered during resolution of the pathname in
- .IR address .
- .TP
- .BR ENAMETOOLONG
- .br
- The length of a pathname exceeds
- {PATH_MAX},
- or pathname resolution of a symbolic link produced an intermediate
- result with a length that exceeds
- {PATH_MAX}.
- .LP
- .IR "The following sections are informative."
- .SH EXAMPLES
- The following code segment shows how to create a socket and
- bind it to a name in the AF_UNIX domain.
- .sp
- .RS 4
- .nf
- #define MY_SOCK_PATH "/somepath"
- .P
- int sfd;
- struct sockaddr_un my_addr;
- .P
- sfd = socket(AF_UNIX, SOCK_STREAM, 0);
- if (sfd == -1)
- /* Handle error */;
- .P
- memset(&my_addr, \(aq\e0\(aq, sizeof(struct sockaddr_un));
- /* Clear structure */
- my_addr.sun_family = AF_UNIX;
- strncpy(my_addr.sun_path, MY_SOCK_PATH, sizeof(my_addr.sun_path) -1);
- .P
- if (bind(sfd, (struct sockaddr *) &my_addr,
- sizeof(struct sockaddr_un)) == -1)
- /* Handle error */;
- .fi
- .P
- .RE
- .SH "APPLICATION USAGE"
- An application program can retrieve the assigned socket name with the
- \fIgetsockname\fR()
- function.
- .SH RATIONALE
- None.
- .SH "FUTURE DIRECTIONS"
- None.
- .SH "SEE ALSO"
- .IR "\fIconnect\fR\^(\|)",
- .IR "\fIgetsockname\fR\^(\|)",
- .IR "\fIlisten\fR\^(\|)",
- .IR "\fIsocket\fR\^(\|)"
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "\fB<sys_socket.h>\fP"
- .\"
- .SH COPYRIGHT
- Portions of this text are reprinted and reproduced in electronic form
- from IEEE Std 1003.1-2017, Standard for Information Technology
- -- Portable Operating System Interface (POSIX), The Open Group Base
- Specifications Issue 7, 2018 Edition,
- Copyright (C) 2018 by the Institute of
- Electrical and Electronics Engineers, Inc and The Open Group.
- In the event of any discrepancy between this version and the original IEEE and
- The Open Group Standard, the original IEEE and The Open Group Standard
- is the referee document. The original Standard can be obtained online at
- http://www.opengroup.org/unix/online.html .
- .PP
- Any typographical or formatting errors that appear
- in this page are most likely
- to have been introduced during the conversion of the source files to
- man page format. To report such errors, see
- https://www.kernel.org/doc/man-pages/reporting_bugs.html .