http3.md (1056B)
1 --- 2 c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3 SPDX-License-Identifier: curl 4 Long: http3 5 Tags: Versions 6 Protocols: HTTP 7 Added: 7.66.0 8 Mutexed: http1.1 http1.0 http2 http2-prior-knowledge http3-only 9 Requires: HTTP/3 10 Help: Use HTTP/3 11 Category: http 12 Multi: mutex 13 See-also: 14 - http1.1 15 - http2 16 Example: 17 - --http3 $URL 18 --- 19 20 # `--http3` 21 22 Attempt HTTP/3 to the host in the URL, but fallback to earlier HTTP versions 23 if the HTTP/3 connection establishment fails or is slow. HTTP/3 is only 24 available for HTTPS and not for HTTP URLs. 25 26 This option allows a user to avoid using the Alt-Svc method of upgrading to 27 HTTP/3 when you know or suspect that the target speaks HTTP/3 on the given 28 host and port. 29 30 When asked to use HTTP/3, curl issues a separate attempt to use older HTTP 31 versions with a slight delay, so if the HTTP/3 transfer fails or is slow, curl 32 still tries to proceed with an older HTTP version. The fallback performs the 33 regular negotiation between HTTP/1 and HTTP/2. 34 35 Use --http3-only for similar functionality *without* a fallback.