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CURLOPT_HTTP_VERSION(3)    curl_easy_setopt options    CURLOPT_HTTP_VERSION(3)

NAME

CURLOPT_HTTP_VERSION - specify HTTP protocol version to use

SYNOPSIS

#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTP_VERSION, long version);

DESCRIPTION

Pass version a long, set to one of the values described below. They ask libcurl to use the specific HTTP versions. This is not sensible to do unless you have a good reason. You have to set this option if you want to use libcurl's HTTP/2 support. Note that the HTTP version is just a request. libcurl will still prioritize to re-use an existing connection so it might then re-use a connection using a HTTP version you haven't asked for. CURL_HTTP_VERSION_NONE We don't care about what version the library uses. libcurl will use whatever it thinks fit. CURL_HTTP_VERSION_1_0 Enforce HTTP 1.0 requests. CURL_HTTP_VERSION_1_1 Enforce HTTP 1.1 requests. CURL_HTTP_VERSION_2_0 Attempt HTTP 2 requests. libcurl will fall back to HTTP 1.1 if HTTP 2 can't be negotiated with the server. (Added in 7.33.0) The alias CURL_HTTP_VERSION_2 was added in 7.43.0 to better reflect the actual protocol name. CURL_HTTP_VERSION_2TLS Attempt HTTP 2 over TLS (HTTPS) only. libcurl will fall back to HTTP 1.1 if HTTP 2 can't be negotiated with the HTTPS server. For clear text HTTP servers, libcurl will use 1.1. (Added in 7.47.0) CURL_HTTP_VERSION_2_PRIOR_KNOWLEDGE Issue non-TLS HTTP requests using HTTP/2 without HTTP/1.1 Upgrade. It requires prior knowledge that the server supports HTTP/2 straight away. HTTPS requests will still do HTTP/2 the standard way with negotiated protocol version in the TLS handshake. (Added in 7.49.0)

DEFAULT

Since curl 7.62.0: CURL_HTTP_VERSION_2TLS Before that: CURL_HTTP_VERSION_1_1

PROTOCOLS

HTTP

EXAMPLE

CURL *curl = curl_easy_init(); if(curl) { CURLcode ret; curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/"); curl_easy_setopt(curl, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2TLS); ret = curl_easy_perform(curl); if(ret == CURLE_HTTP_RETURNED_ERROR) { /* an HTTP response error problem */ } }

AVAILABILITY

Along with HTTP

RETURN VALUE

Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO

CURLOPT_SSLVERSION(3), CURLOPT_HTTP200ALIASES(3), CURLOPT_HTTP09_ALLOWED(3), libcurl 7.65.1 December 17, 2018 CURLOPT_HTTP_VERSION(3)

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