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CURLOPT_TCP_FASTOPEN(3) | Library Functions Manual | CURLOPT_TCP_FASTOPEN(3) |
NAME¶
CURLOPT_TCP_FASTOPEN - TCP Fast Open
SYNOPSIS¶
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_FASTOPEN, long enable);
DESCRIPTION¶
Pass a long as parameter set to 1L to enable or 0 to disable.
TCP Fast Open (RFC 7413) is a mechanism that allows data to be carried in the SYN and SYN-ACK packets and consumed by the receiving end during the initial connection handshake, saving up to one full round-trip time (RTT).
Beware: the TLS session cache does not work when TCP Fast Open is enabled. TCP Fast Open is also known to be problematic on or across certain networks.
DEFAULT¶
0
PROTOCOLS¶
All
EXAMPLE¶
int main(void) {
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
curl_easy_setopt(curl, CURLOPT_TCP_FASTOPEN, 1L);
curl_easy_perform(curl);
} }
AVAILABILITY¶
Added in 7.49.0. This option is currently only supported on Linux and macOS 10.11 or later.
RETURN VALUE¶
Returns CURLE_OK if fast open is supported by the operating system, otherwise returns CURLE_NOT_BUILT_IN.
SEE ALSO¶
CURLOPT_SSL_FALSESTART(3)
2024-06-09 | libcurl |