BIND(2) System Calls Manual BIND(2)

bind — bind a name to a socket

#include <sys/socket.h>

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

() assigns a name to an unnamed socket. When a socket is created with socket(2) it exists in a name space (address family) but has no name assigned. bind() requests that address be assigned to the socket.

Binding a name 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 unlink(2)).

The rules used in name binding vary between communication domains. Consult the manual entries in section 4 for detailed information.

Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and the global integer variable errno is set to indicate the error.

The bind() system call will fail if:

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The requested address is protected, and the current user has inadequate permission to access it.
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The specified address is already in use.
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The specified address is not available from the local machine.
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address is not valid for the address family of socket.
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socket is not a valid file descriptor.
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socket is a null pointer.
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The address parameter is not in a valid part of the user address space.
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socket is already bound to an address and the protocol does not support binding to a new address. Alternatively, socket may have been shut down.
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socket does not refer to a socket.
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socket is not of a type that can be bound to an address.

The following errors are specific to binding names in the UNIX domain.

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A component of the path prefix does not allow searching or the node's parent directory denies write permission.
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A file already exists at the pathname. unlink(2) it first.
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An I/O error occurred while making the directory entry or allocating the inode.
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An empty pathname was specified.
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Too many symbolic links were encountered in translating the pathname. This is taken to be indicative of a looping symbolic link.
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A component of a pathname exceeded {NAME_MAX} characters, or an entire path name exceeded {PATH_MAX} characters.
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A component of the path name does not refer to an existing file.
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A component of the path prefix is not a directory.
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The name would reside on a read-only file system.

#include <sys/types.h> #include <sys/socket.h>

The include file <sys/types.h> is necessary.

connect(2), connectx(2), getsockname(2), listen(2), socket(2), compat(5)

The bind() function call appeared in 4.2BSD.

March 18, 2015 BSD 4.2