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CURLOPT_HTTP09_ALLOWED - allow HTTP/0.9 response

NAME  SYNOPSIS  DESCRIPTION  DEFAULT  PROTOCOLS  EXAMPLE  HISTORY  AVAILABILITY  RETURN VALUE  SEE ALSO 

NAME

CURLOPT_HTTP09_ALLOWED − allow HTTP/0.9 response

SYNOPSIS

#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

This functionality affects http only

EXAMPLE

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

Added in curl 7.64.0

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).

SEE ALSO

CURLOPT_HTTP_VERSION(3), CURLOPT_SSLVERSION(3)


Updated 2026-06-01 - jenkler.se | uex.se