CURLINFO_USED_PROXY(3) Library Functions Manual CURLINFO_USED_PROXY(3)

CURLINFO_USED_PROXY - whether the transfer used a proxy

#include <curl/curl.h>
CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_USED_PROXY,
                           long *authp);

Pass a pointer to a long. It gets set to zero set if no proxy was used in the previous transfer or a non-zero value if a proxy was used.

This functionality affects all supported protocols

int main(int argc, char *argv[])
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, argv[1]);
    curl_easy_setopt(curl, CURLOPT_PROXY, "http://127.0.0.1:80");
    curl_easy_setopt(curl, CURLOPT_NOPROXY, "example.com");
    res = curl_easy_perform(curl);
    if(!res) {
      /* extract the available proxy authentication types */
      long used;
      res = curl_easy_getinfo(curl, CURLINFO_USED_PROXY, &used);
      if(!res) {
        printf("The proxy was %sused\n", used ? "": "NOT ");
      }
    }
    curl_easy_cleanup(curl);
  }
}

Added in curl 8.7.0

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

CURLOPT_NOPROXY(3), CURLOPT_PROXY(3), curl_easy_getinfo(3), curl_easy_setopt(3)

2024-09-18 libcurl