CURLOPT_REFERER(3)

💅 CURLOPT_REFERER — the HTTP referer header

okay so bestie, welcome to CURLOPT_REFERER from the Library Functions Manual. yes this is literally the libcurl page for the referer header and no I will not be calm about it 🎀

---

✨ SYNOPSIS ✨

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_REFERER, char *where);

that's it. that's the whole vibe check. 🦋

---

🌸 DESCRIPTION 🌸

so you pass a pointer to a null-terminated string as the parameter, right? and that string is what gets used to set the Referer: header field in the HTTP request you send to the remote server. it's giving "hey bestie, I came from over there" energy 💖

and like — you can set any custom header with CURLOPT_HTTPHEADER(3) if you're feeling extra. no gatekeeping here 👑

the application does not have to keep the string around after setting this option. so go ahead, let it go, free yourself, it's fine 😌✨

Using this option multiple times makes the last set string override the previous ones. last one wins, no cap, the earlier ones are simply not the main character anymore 💀 and if you set it to NULL you disable its use again. bye bye referer 🫶

---

🎀 DEFAULT 🎀

NULL

(default is nothing, we start with nothing, it's a whole blank slate moment 💅)

---

🌈 PROTOCOLS 🌈

this functionality affects http only. literally just http. that's the whole list. periodt. 🍓

---

⭐ EXAMPLE ⭐

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    /* tell it where we found the link to this place */
    curl_easy_setopt(curl, CURLOPT_REFERER, "https://example.org/me.html");

    curl_easy_perform(curl);
  }
}

look at that comment — /* tell it where we found the link to this place */ — iconic, self-explanatory, 10/10, no notes 🧚

---

🦋 AVAILABILITY 🦋

Added in curl 7.1. ancient. vintage. a classic. she's been here since forever and she ate 🔥

---

💜 RETURN VALUE 💜

curl_easy_setopt(3) returns a CURLcode indicating success or error. that's the whole thing, she tells you how it went 🫶

• CURLE_OK (0) means everything was OK ✨ slay
• non-zero means an error occurred 😭 see libcurl-errors(3) for the tea

---

👑 SEE ALSO 👑

• CURLINFO_REDIRECT_URL(3)
• CURLINFO_REFERER(3)
• CURLOPT_HTTPHEADER(3)
• CURLOPT_USERAGENT(3)

go read them, they're all besties, iykyk 💖

---

ngl this page is short and sweet and that's her main character energy. no warnings, no bugs, no drama. just referer. 💅

kisses, this was libcurl, dated 2026-10-12 — mwah, see you in the next manpage bestie 🌸🎀💜