c: Copyright (C) Daniel Stenberg, daniel@haxx.se, et al. SPDX-License-Identifier: curl Title: CURLOPT_SSL_ENABLE_ALPN Section: 3 Source: libcurl See-also:
CURLOPT_SSL_ENABLE_ALPN - Application Layer Protocol Negotiation
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_ENABLE_ALPN, long npn);
Pass a long as parameter, 0 or 1 where 1 is for enable and 0 for disable. This option enables/disables ALPN in the SSL handshake (if the SSL backend libcurl is built to use supports it), which can be used to negotiate http2.
1, enabled
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode res;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
curl_easy_setopt(curl, CURLOPT_SSL_ENABLE_ALPN, 0L);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
Added in 7.36.0
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.