CURLOPT_HTTP09_ALLOWED(3) Library Functions Manual CURLOPT_HTTP09_ALLOWED(3)
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 ret;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
curl_easy_setopt(curl, CURLOPT_HTTP09_ALLOWED, 1L);
ret = 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)
libcurl 2026-07-12 CURLOPT_HTTP09_ALLOWED(3)
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