bind(3p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

BIND(3P)                POSIX Programmer's Manual               BIND(3P)

PROLOG         top

       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.

NAME         top

       bind — bind a name to a socket

SYNOPSIS         top

       #include <sys/socket.h>

       int bind(int socket, const struct sockaddr *address,
           socklen_t address_len);

DESCRIPTION         top

       The bind() function shall assign a local socket address address
       to a socket identified by descriptor socket that has no local
       socket address assigned. Sockets created with the socket()
       function are initially unnamed; they are identified only by their
       address family.

       The bind() function takes the following arguments:

       socket      Specifies the file descriptor of the socket to be
                   bound.

       address     Points to a 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.

       address_len Specifies the length of the sockaddr structure
                   pointed to by the address argument.

       The socket specified by socket may require the process to have
       appropriate privileges to use the bind() function.

       If the address family of the socket is AF_UNIX and the pathname
       in address names a symbolic link, bind() shall fail and set errno
       to [EADDRINUSE].

       If the socket address cannot be assigned immediately and
       O_NONBLOCK is set for the file descriptor for the socket, bind()
       shall fail and set errno to [EINPROGRESS], but the assignment
       request shall not be aborted, and the assignment shall be
       completed asynchronously. Subsequent calls to bind() for the same
       socket, before the assignment is completed, shall fail and set
       errno to [EALREADY].

       When the assignment has been performed asynchronously, pselect(),
       select(), and poll() shall indicate that the file descriptor for
       the socket is ready for reading and writing.

RETURN VALUE         top

       Upon successful completion, bind() shall return 0; otherwise, -1
       shall be returned and errno set to indicate the error.

ERRORS         top

       The bind() function shall fail if:

       EADDRINUSE
              The specified address is already in use.

       EADDRNOTAVAIL
              The specified address is not available from the local
              machine.

       EAFNOSUPPORT
              The specified address is not a valid address for the
              address family of the specified socket.

       EALREADY
              An assignment request is already in progress for the
              specified socket.

       EBADF  The socket argument is not a valid file descriptor.

       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.

       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.

       ENOBUFS
              Insufficient resources were available to complete the
              call.

       ENOTSOCK
              The socket argument does not refer to a socket.

       EOPNOTSUPP
              The socket type of the specified socket does not support
              binding to an address.

       If the address family of the socket is AF_UNIX, then bind() shall
       fail if:

       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.

       EDESTADDRREQ or EISDIR
              The address argument is a null pointer.

       EIO    An I/O error occurred.

       ELOOP  A loop exists in symbolic links encountered during
              resolution of the pathname in address.

       ENAMETOOLONG
              The length of a component of a pathname is longer than
              {NAME_MAX}.

       ENOENT A component of the path prefix of the pathname in address
              does not name an existing file or the pathname is an empty
              string.

       ENOENT or ENOTDIR
              The pathname in address contains at least one non-<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 [ENOENT] error
              shall not occur.

       ENOTDIR
              A component of the path prefix of the pathname in address
              names an existing file that is neither a directory nor a
              symbolic link to a directory, or the pathname in address
              contains at least one non-<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.

       EROFS  The name would reside on a read-only file system.

       The bind() function may fail if:

       EACCES The specified address is protected and the current user
              does not have permission to bind to it.

       EINVAL The address_len argument is not a valid length for the
              address family.

       EISCONN
              The socket is already connected.

       ELOOP  More than {SYMLOOP_MAX} symbolic links were encountered
              during resolution of the pathname in address.

       ENAMETOOLONG
              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}.

       The following sections are informative.

EXAMPLES         top

       The following code segment shows how to create a socket and bind
       it to a name in the AF_UNIX domain.

           #define MY_SOCK_PATH "/somepath"

           int sfd;
           struct sockaddr_un my_addr;

           sfd = socket(AF_UNIX, SOCK_STREAM, 0);
           if (sfd == -1)
               /* Handle error */;

           memset(&my_addr, '\0', 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);

           if (bind(sfd, (struct sockaddr *) &my_addr,
               sizeof(struct sockaddr_un)) == -1)
               /* Handle error */;

APPLICATION USAGE         top

       An application program can retrieve the assigned socket name with
       the getsockname() function.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       connect(3p), getsockname(3p), listen(3p), socket(3p)

       The Base Definitions volume of POSIX.1‐2017, sys_socket.h(0p)

COPYRIGHT         top

       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 .

       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 .

IEEE/The Open Group               2017                          BIND(3P)

Pages that refer to this page: netdb.h(0p)sys_socket.h(0p)sys_un.h(0p)accept(3p)connect(3p)getpeername(3p)getsockname(3p)getsockopt(3p)setsockopt(3p)socket(3p)