---
name: "ares_set_socket_configure_callback"
section: "3"
platform: "linux"
package: "c-ares"
version: "1.34.9-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/ares_set_socket_configure_callback"
---

# ares\_set\_socket\_configure\_callback(3)

Set a socket configuration callback

## NAME

ares\_set\_socket\_configure\_callback - Set a socket configuration callback

## SYNOPSIS

```
#include <ares.h>
typedef int (*ares_sock_config_callback)(ares_socket_t socket_fd,
                                         int type,
                                         void *userdata)
void ares_set_socket_configure_callback(ares_channel_t *channel,
                                        ares_sock_config_callback callback,
                                        void *userdata)
```

## DESCRIPTION

This function sets a *callback* in the given ares channel handle. Cannot be used when **ARES\_OPT\_EVENT\_THREAD** is passed to *[ares\_init\_options(3)](/ares_init_options/3.md)*.

This callback function will be invoked after the socket has been created, but before it has been connected to the remote server, which is an ideal time to configure various socket options.  The callback must return ARES\_SUCCESS if things are fine, or return -1 to signal an error. A returned error will abort the ares operation.

The callback is invoked while c-ares is part-way through opening a connection.  It must not call any c-ares function on the same channel; see *[ares\_set\_socket\_functions(3)](/ares_set_socket_functions/3.md)*.

## SEE ALSO

[**ares\_init\_options**(3)](/ares_init_options/3.md), [**ares\_set\_socket\_callback**(3)](/ares_set_socket_callback/3.md)

## AVAILABILITY

[ares\_set\_socket\_configure\_callback(3)](/ares_set_socket_configure_callback/3.md) was added in c-ares 1.11.0