---
name: "CURLINFO_LASTSOCKET"
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_LASTSOCKET"
---

# CURLINFO\_LASTSOCKET(3)

last socket used

## NAME

CURLINFO\_LASTSOCKET - last socket used

## SYNOPSIS

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

## DESCRIPTION

Deprecated. Use *[CURLINFO\_ACTIVESOCKET(3)](/CURLINFO_ACTIVESOCKET/3.md)* instead.

Pass a pointer to a long to receive the last socket used by this curl session. If the socket is no longer valid, -1 is returned. When you finish working with the socket, you must call *[curl\_easy\_cleanup(3)](/curl_easy_cleanup/3.md)* as usual and let libcurl close the socket and cleanup other resources associated with the handle. This is typically used in combination with *[CURLOPT\_CONNECT\_ONLY(3)](/CURLOPT_CONNECT_ONLY/3.md)*.

NOTE: this API is deprecated since it is not working on win64 where the SOCKET type is 64 bits large while its 'long' is 32 bits. Use the *[CURLINFO\_ACTIVESOCKET(3)](/CURLINFO_ACTIVESOCKET/3.md)* instead, if possible.

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    long sockfd; /* does not work on win64 */
    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_LASTSOCKET, &sockfd);
    if(!result && sockfd != -1) {
      /* operate on sockfd */
    }
    curl_easy_cleanup(curl);
  }
}
```

## DEPRECATED

Deprecated since 7.45.0.

## AVAILABILITY

Added in curl 7.15.2

## 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\_ACTIVESOCKET**(3)](/CURLINFO_ACTIVESOCKET/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)