CURLINFO\_LASTSOCKET(3) Library Functions Manual CURLINFO\_LASTSOCKET(3)

# [NAME](#NAME)

CURLINFO\_LASTSOCKET - last socket used

# [SYNOPSIS](#SYNOPSIS)

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

# [DESCRIPTION](#DESCRIPTION)

Deprecated. Use [*CURLINFO\_ACTIVESOCKET(3)*](/man/os/curl/CURLINFO_ACTIVESOCKET.3) 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 If the socket is no longer valid, -1 is returned.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)*](/man/os/curl/curl_easy_cleanup.3) 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)*](/man/os/curl/CURLOPT_CONNECT_ONLY.3).

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)*](/man/os/curl/CURLINFO_ACTIVESOCKET.3) instead, if possible.

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#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)

Deprecated since 7.45.0.

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.15.2

# [RETURN VALUE](#RETURN_VALUE)

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

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

# [SEE ALSO](#SEE_ALSO)

[**CURLINFO\_ACTIVESOCKET**(3)](/man/os/curl/CURLINFO_ACTIVESOCKET.3), [**CURLOPT\_CONNECT\_ONLY**(3)](/man/os/curl/CURLOPT_CONNECT_ONLY.3), [**curl\_easy\_getinfo**(3)](/man/os/curl/curl_easy_getinfo.3), [**curl\_easy\_setopt**(3)](/man/os/curl/curl_easy_setopt.3)

2026-10-19 libcurl

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Document: CURLINFO_LASTSOCKET(3) from curl 8.23.0-r1 (Chainguard OS)
Source: https://github.com/curl/curl.git