1BIND(3P) POSIX Programmer's Manual BIND(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 bind — bind a name to a socket
13
15 #include <sys/socket.h>
16 int bind(int socket, const struct sockaddr *address,
18 socklen_t address_len);
19
21 The bind() function shall assign a local socket address address to a
22 socket identified by descriptor socket that has no local socket address
23 assigned. Sockets created with the socket() function are initially
24 unnamed; they are identified only by their address family.
25 The bind() function takes the following arguments:
27 socket Specifies the file descriptor of the socket to be bound.
29 address Points to a sockaddr structure containing the address to be
31 bound to the socket. The length and format of the address
32 depend on the address family of the socket.
33 address_len Specifies the length of the sockaddr structure pointed to
35 by the address argument.
36 The socket specified by socket may require the process to have appro‐
38 priate privileges to use the bind() function.
39 If the address family of the socket is AF_UNIX and the pathname in
41 address names a symbolic link, bind() shall fail and set errno to [EAD‐
42 DRINUSE].
43 If the socket address cannot be assigned immediately and O_NONBLOCK is
45 set for the file descriptor for the socket, bind() shall fail and set
46 errno to [EINPROGRESS], but the assignment request shall not be
47 aborted, and the assignment shall be completed asynchronously. Subse‐
48 quent calls to bind() for the same socket, before the assignment is
49 completed, shall fail and set errno to [EALREADY].
50 When the assignment has been performed asynchronously, pselect(),
52 select(), and poll() shall indicate that the file descriptor for the
53 socket is ready for reading and writing.
54
56 Upon successful completion, bind() shall return 0; otherwise, -1 shall
57 be returned and errno set to indicate the error.
58
60 The bind() function shall fail if:
61 EADDRINUSE
63 The specified address is already in use.
64 EADDRNOTAVAIL
66 The specified address is not available from the local machine.
67 EAFNOSUPPORT
69 The specified address is not a valid address for the address
70 family of the specified socket.
71 EALREADY
73 An assignment request is already in progress for the specified
74 socket.
75 EBADF The socket argument is not a valid file descriptor.
77 EINPROGRESS
79 O_NONBLOCK is set for the file descriptor for the socket and the
80 assignment cannot be immediately performed; the assignment shall
81 be performed asynchronously.
82 EINVAL The socket is already bound to an address, and the protocol does
84 not support binding to a new address; or the socket has been
85 shut down.
86 ENOBUFS
88 Insufficient resources were available to complete the call.
89 ENOTSOCK
91 The socket argument does not refer to a socket.
92 EOPNOTSUPP
94 The socket type of the specified socket does not support binding
95 to an address.
96 If the address family of the socket is AF_UNIX, then bind() shall fail
98 if:
99 EACCES A component of the path prefix denies search permission, or the
101 requested name requires writing in a directory with a mode that
102 denies write permission.
103 EDESTADDRREQ or EISDIR
105 The address argument is a null pointer.
106 EIO An I/O error occurred.
108 ELOOP A loop exists in symbolic links encountered during resolution of
110 the pathname in address.
111 ENAMETOOLONG
113 The length of a component of a pathname is longer than
114 {NAME_MAX}.
115 ENOENT A component of the path prefix of the pathname in address does
117 not name an existing file or the pathname is an empty string.
118 ENOENT or ENOTDIR
120 The pathname in address contains at least one non-<slash> char‐
121 acter and ends with one or more trailing <slash> characters. If
122 the pathname without the trailing <slash> characters would name
123 an existing file, an [ENOENT] error shall not occur.
124 ENOTDIR
126 A component of the path prefix of the pathname in address names
127 an existing file that is neither a directory nor a symbolic link
128 to a directory, or the pathname in address contains at least one
129 non-<slash> character and ends with one or more trailing <slash>
130 characters and the last pathname component names an existing
131 file that is neither a directory nor a symbolic link to a direc‐
132 tory.
133 EROFS The name would reside on a read-only file system.
135 The bind() function may fail if:
137 EACCES The specified address is protected and the current user does not
139 have permission to bind to it.
140 EINVAL The address_len argument is not a valid length for the address
142 family.
143 EISCONN
145 The socket is already connected.
146 ELOOP More than {SYMLOOP_MAX} symbolic links were encountered during
148 resolution of the pathname in address.
149 ENAMETOOLONG
151 The length of a pathname exceeds {PATH_MAX}, or pathname resolu‐
152 tion of a symbolic link produced an intermediate result with a
153 length that exceeds {PATH_MAX}.
154 The following sections are informative.
156
158 The following code segment shows how to create a socket and bind it to
159 a name in the AF_UNIX domain.
160 #define MY_SOCK_PATH "/somepath"
163 int sfd;
165 struct sockaddr_un my_addr;
166 sfd = socket(AF_UNIX, SOCK_STREAM, 0);
168 if (sfd == -1)
169 /* Handle error */;
170 memset(&my_addr, '\0', sizeof(struct sockaddr_un));
172 /* Clear structure */
173 my_addr.sun_family = AF_UNIX;
174 strncpy(my_addr.sun_path, MY_SOCK_PATH, sizeof(my_addr.sun_path) -1);
175 if (bind(sfd, (struct sockaddr *) &my_addr,
177 sizeof(struct sockaddr_un)) == -1)
178 /* Handle error */;
179
181 An application program can retrieve the assigned socket name with the
182 getsockname() function.
183
185 None.
186
188 None.
189
191 connect(), getsockname(), listen(), socket()
192 The Base Definitions volume of POSIX.1‐2017, <sys_socket.h>
194
196 Portions of this text are reprinted and reproduced in electronic form
197 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
198 table Operating System Interface (POSIX), The Open Group Base Specifi‐
199 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
200 Electrical and Electronics Engineers, Inc and The Open Group. In the
201 event of any discrepancy between this version and the original IEEE and
202 The Open Group Standard, the original IEEE and The Open Group Standard
203 is the referee document. The original Standard can be obtained online
204 at http://www.opengroup.org/unix/online.html .
205 Any typographical or formatting errors that appear in this page are
207 most likely to have been introduced during the conversion of the source
208 files to man page format. To report such errors, see https://www.ker‐
209 nel.org/doc/man-pages/reporting_bugs.html .
210IEEE/The Open Group 2017 BIND(3P)