---
name: "sctp_bindx"
section: "3"
platform: "linux"
package: "lksctp-tools"
version: "1.0.21-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/sctp_bindx"
---

# sctp\_bindx(3)

Add or remove bind addresses on a socket.

## NAME

sctp\_bindx - Add or remove bind addresses on a socket.

## SYNOPSIS

```
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/sctp.h>

int sctp_bindx(int sd, struct sockaddr * addrs, int addrcnt,
               int flags);
```

## DESCRIPTION

**sctp\_bindx** adds or removes a set of bind addresses passed in the array *addrs* to/from the socket *sd.* *addrcnt* is the number of addresses in the array and the *flags* paramater indicates if the addresses need to be added or removed.

If *sd* is an IPv4 socket, the addresses passed must be IPv4 addresses. If *sd* is an IPv6 socket, the addresses passed can be either IPv4 or IPv6 addresses.

*addrs* is a pointer to an array of one or more socket addresses. Each address is contained in its appropriate structure(i.e. struct sockaddr\_in or struct sockaddr\_in6). The family of the address type must be used to distinguish the address length. The caller specifies the number of addresses in the array with *addrcnt.*

The *flags* parameter can be either **SCTP\_BINDX\_ADD\_ADDR** or **SCTP\_BINDX\_REM\_ADDR.** An application can use **SCTP\_BINDX\_ADD\_ADDR** to associate additional addresses with an endpoint after calling **[bind(2)](/bind/2.md).** **SCTP\_BINDX\_REM\_ADDR** directs SCTP to remove the given addresses from the association. A caller may not remove all addresses from an association. It will fail with **EINVAL.**

## RETURN VALUE

On success, 0 is returned. On failure, -1 is returned, and *errno* is set appropriately.

## ERRORS

- **EBADF**

  *sd* is not a valid descriptor.

- **ENOTSOCK**

  *sd* is a descriptor for a file, not a socket.

- **EFAULT**

  Error while copying in or out from the user address space.

- **EINVAL**

  Invalid port or address or trying to remove all addresses from an association.

- **EACCES**

  The address is protected, and the user is not the super-user.

## SEE ALSO

[**sctp**(7)](/sctp/7.md) [**sctp\_sendmsg**(3)](/sctp_sendmsg/3.md), [**sctp\_sendv**(3)](/sctp_sendv/3.md), [**sctp\_send**(3)](/sctp_send/3.md), [**sctp\_recvmsg**(3)](/sctp_recvmsg/3.md), [**sctp\_recvv**(3)](/sctp_recvv/3.md), [**sctp\_peeloff**(3)](/sctp_peeloff/3.md), [**sctp\_getpaddrs**(3)](/sctp_getpaddrs/3.md), [**sctp\_getladdrs**(3)](/sctp_getladdrs/3.md), [**sctp\_opt\_info**(3)](/sctp_opt_info/3.md), [**sctp\_connectx**(3)](/sctp_connectx/3.md)