Provided by: libcurl4-doc_8.9.1-2ubuntu2.1_all
NAME
CURLOPT_ALTSVC - alt-svc cache filename
SYNOPSIS
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ALTSVC, char *filename);
DESCRIPTION
Pass in a pointer to a filename to instruct libcurl to use that file as the Alt-Svc cache to read existing cache contents from and possibly also write it back to after a transfer, unless CURLALTSVC_READONLYFILE is set in CURLOPT_ALTSVC_CTRL(3). Specify a blank filename ("") to make libcurl not load from a file at all.
DEFAULT
NULL. The alt-svc cache is not read nor written to file.
PROTOCOLS
This functionality affects http only
EXAMPLE
int main(void) { CURL *curl = curl_easy_init(); if(curl) { curl_easy_setopt(curl, CURLOPT_ALTSVC_CTRL, CURLALTSVC_H1); curl_easy_setopt(curl, CURLOPT_ALTSVC, "altsvc-cache.txt"); curl_easy_perform(curl); } }
FILE FORMAT
A text based file with one line per alt-svc entry and each line consists of nine space-separated fields. An example line could look like h2 www.example.com 8443 h3 second.example.com 443 "20190808 06:18:37" 1 0 The fields of that line are: h2 ALPN id for the source origin www.example.comp Hostname for the source origin 8443 Port number for the source origin h3 ALPN id for the destination host second.example.com Hostname for the destination host 443 Port number for the destination host 2019* Expiration date and time of this entry within double quotes. The date format is "YYYYMMDD HH:MM:SS" and the time zone is GMT. 1 Boolean (1 or 0) if "persist" was set for this entry 0 Integer priority value (not currently used)
AVAILABILITY
Added in curl 7.64.1
RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
SEE ALSO
CURLOPT_ALTSVC_CTRL(3), CURLOPT_CONNECT_TO(3), CURLOPT_COOKIEFILE(3), CURLOPT_RESOLVE(3)