CURLINFO_ACTIVESOCKET(3) Library Functions Manual CURLINFO_ACTIVESOCKET(3)
NAME
CURLINFO_ACTIVESOCKET - get the 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socket is no longer valid, CURL_SOCKET_BAD is returned.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) as
usual on the easy handle and let libcurl close the socket and cleanup
other resources associated with the handle. This option returns the ac-
tive socket only after the transfer is complete, and is typically used
in combination with CURLOPT_CONNECT_ONLY(3), which skips the transfer
phase.
CURLINFO_ACTIVESOCKET(3) was added as a replacement for CURLINFO_LAST-
SOCKET(3) 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 res;
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);
res = curl_easy_perform(curl);
if(res != CURLE_OK) {
printf("Error: %s\n", curl_easy_strerror(res));
curl_easy_cleanup(curl);
return 1;
}
/* Extract the socket from the curl handle */
res = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd);
if(!res && sockfd != CURL_SOCKET_BAD) {
/* operate on sockfd */
}
curl_easy_cleanup(curl);
}
}
AVAILABILITY
Added in curl 7.45.0
RETURN VALUE
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).
SEE ALSO
CURLINFO_LASTSOCKET(3), CURLOPT_CONNECT_ONLY(3), curl_easy_getinfo(3),
curl_easy_setopt(3)
libcurl 2026-07-12 CURLINFO_ACTIVESOCKET(3)
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