CURLINFO_USED_PROXY - whether the transfer used a proxy

Added in curl 8.7.0

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.

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); } }

CURLINFO_USED_PROXY - whether the transfer used a proxy

This functionality affects all supported protocols

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).

CURLOPT_NOPROXY(3), CURLOPT_PROXY(3), curl_easy_getinfo(3), curl_easy_setopt(3) libcurl 2025-06-16 CURLINFO_USED_PROXY(3)

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