BIND(2) BSD System Calls Manual BIND(2)NAMEbind — assign a local protocol address to a socket
Standard C Library (libc, -lc)
bind(int s, const struct sockaddr *addr, socklen_t addrlen);
The bind() system call assigns the local protocol address to a socket.
When a socket is created with socket(2) it exists in an address family
space but has no protocol address assigned. The bind() system call
requests that addr be assigned to the socket.
Binding an address in the UNIX domain creates a socket in the file system
that must be deleted by the caller when it is no longer needed (using
The rules used in address binding vary between communication domains.
Consult the manual entries in section 4 for detailed information.
For maximum portability, you should always zero the socket address struc‐
ture before populating it and passing it to bind().
The bind() function returns the value 0 if successful; otherwise the
value -1 is returned and the global variable errno is set to indicate the
The bind() system call will fail if:
[EAGAIN] Kernel resources to complete the request are temporar‐
[EBADF] The s argument is not a valid descriptor.
[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.
[ENOTSOCK] The s argument is not a socket.
[EADDRNOTAVAIL] The specified address is not available from the local
[EADDRINUSE] The specified address is already in use.
[EACCES] The requested address is protected, and the current
user has inadequate permission to access it.
[EFAULT] The addr argument is not in a valid part of the user
The following errors are specific to binding addresses in the UNIX
[ENOTDIR] A component of the path prefix is not a directory.
A component of a pathname exceeded 255 characters, or an
entire path name exceeded 1023 characters.
[ENOENT] A prefix component of the path name does not exist.
[ELOOP] Too many symbolic links were encountered in translating the
[EIO] An I/O error occurred while making the directory entry or
allocating the inode.
[EROFS] The name would reside on a read-only file system.
[EISDIR] An empty pathname was specified.
SEE ALSOconnect(2), getsockname(2), listen(2), socket(2)HISTORY
The bind() system call appeared in 4.2BSD.
BSD June 4, 1993 BSD