---
name: "CURLINFO_ACTIVESOCKET"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLINFO_ACTIVESOCKET"
---

# CURLINFO\_ACTIVESOCKET(3)

active socket

## NAME

CURLINFO\_ACTIVESOCKET - active socket

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_ACTIVESOCKET,
                           curl_socket_t *socket);
```

## DESCRIPTION

Pass a pointer to a curl\_socket\_t to receive the most recently active socket used for the transfer connection by this curl session. If the socket is no longer valid, *CURL\_SOCKET\_BAD* is returned. When you are finished working with the socket, you must call *[curl\_easy\_cleanup(3)](/curl_easy_cleanup/3.md)* as usual on the easy handle and let libcurl close the socket and cleanup other resources associated with the handle. This option returns the active socket only after the transfer is complete, and is typically used in combination with *[CURLOPT\_CONNECT\_ONLY(3)](/CURLOPT_CONNECT_ONLY/3.md)*, which skips the transfer phase.

*[CURLINFO\_ACTIVESOCKET(3)](/CURLINFO_ACTIVESOCKET/3.md)* was added as a replacement for *[CURLINFO\_LASTSOCKET(3)](/CURLINFO_LASTSOCKET/3.md)* since that one is not working on all platforms.

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_socket_t sockfd;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
    /* Do not do the transfer - only connect to host */
    curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1L);
    result = curl_easy_perform(curl);
    if(result != CURLE_OK) {
      printf("Error: %s\n", curl_easy_strerror(result));
      curl_easy_cleanup(curl);
      return 1;
    }
    /* Extract the socket from the curl handle */
    result = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd);
    if(!result && sockfd != CURL_SOCKET_BAD) {
      /* operate on sockfd */
    }
    curl_easy_cleanup(curl);
  }
}
```

## AVAILABILITY

Added in curl 7.45.0

## RETURN VALUE

*[curl\_easy\_getinfo(3)](/curl_easy_getinfo/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLINFO\_LASTSOCKET**(3)](/CURLINFO_LASTSOCKET/3.md), [**CURLOPT\_CONNECT\_ONLY**(3)](/CURLOPT_CONNECT_ONLY/3.md), [**curl\_easy\_getinfo**(3)](/curl_easy_getinfo/3.md), [**curl\_easy\_setopt**(3)](/curl_easy_setopt/3.md)