xref: /aosp_15_r20/external/curl/docs/libcurl/opts/CURLOPT_REFERER.md (revision 6236dae45794135f37c4eb022389c904c8b0090d)

---
c: Copyright (C) Daniel Stenberg, <[email protected]>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_REFERER
Section: 3
Source: libcurl
See-also:
  - CURLINFO_REDIRECT_URL (3)
  - CURLINFO_REFERER (3)
  - CURLOPT_HTTPHEADER (3)
  - CURLOPT_USERAGENT (3)
Protocol:
  - HTTP
Added-in: 7.1
---

# NAME

CURLOPT_REFERER - the HTTP referer header

# SYNOPSIS

~~~c
#include <curl/curl.h>

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

# DESCRIPTION

Pass a pointer to a null-terminated string as parameter. It is used to set the
Referer: header field in the HTTP request sent to the remote server. You can
set any custom header with CURLOPT_HTTPHEADER(3).

The application does not have to keep the string around after setting this
option.

Using this option multiple times makes the last set string override the
previous ones. Set it to NULL to disable its use again.

# DEFAULT

NULL

# %PROTOCOLS%

# EXAMPLE

~~~c
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);
  }
}
~~~

# %AVAILABILITY%

# RETURN VALUE

Returns CURLE_OK if HTTP support is enabled, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.