---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_HTTP09_ALLOWED
Section: 3
Source: libcurl
Protocol:
  - HTTP
See-also:
  - CURLOPT_HTTP_VERSION (3)
  - CURLOPT_SSLVERSION (3)
Added-in: 7.64.0
---

# NAME

CURLOPT_HTTP09_ALLOWED - allow HTTP/0.9 response

# SYNOPSIS

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

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTP09_ALLOWED, long allowed);
~~~

# DESCRIPTION

Pass the long argument *allowed* set to 1L to allow HTTP/0.9 responses.

An HTTP/0.9 response is a server response entirely without headers and only a
body. You can connect to lots of random TCP services and still get a response
that curl might consider to be HTTP/0.9.

# DEFAULT

0

# %PROTOCOLS%

# EXAMPLE

~~~c
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    curl_easy_setopt(curl, CURLOPT_HTTP09_ALLOWED, 1L);
    result = curl_easy_perform(curl);
  }
}
~~~

# HISTORY

curl allowed HTTP/0.9 responses by default before 7.66.0

Since 7.66.0, libcurl requires this option set to 1L to allow HTTP/0.9
responses.

# %AVAILABILITY%

# RETURN VALUE

curl_easy_setopt(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).