curl / libcurl / API / curl_easy_setopt / CURLOPT_CONNECTTIMEOUT

CURLOPT_CONNECTTIMEOUT explained

Name

CURLOPT_CONNECTTIMEOUT - timeout for the connect phase

Synopsis

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

Description

Pass a long. It should contain the maximum time in seconds that you allow the connection phase to the server to take. This timeout only limits the connection phase, it has no impact once it has connected. Set to zero to switch to the default built-in connection timeout - 300 seconds. See also the CURLOPT_TIMEOUT option.

CURLOPT_CONNECTTIMEOUT_MS is the same function but set in milliseconds.

If both CURLOPT_CONNECTTIMEOUT and CURLOPT_CONNECTTIMEOUT_MS are set, the value set last is used.

The "connection phase" is considered complete when the requested TCP, TLS or QUIC handshakes are done.

The connection timeout set with CURLOPT_CONNECTTIMEOUT is included in the general all-covering CURLOPT_TIMEOUT.

With CURLOPT_CONNECTTIMEOUT set to 3 and CURLOPT_TIMEOUT set to 5, the operation can never last longer than 5 seconds, and the connection phase cannot last longer than 3 seconds.

With CURLOPT_CONNECTTIMEOUT set to 4 and CURLOPT_TIMEOUT set to 2, the operation can never last longer than 2 seconds. Including the connection phase.

This option may cause libcurl to use the SIGALRM signal to timeout system calls on builds not using asynch DNS. In unix-like systems, this might cause signals to be used unless CURLOPT_NOSIGNAL is set.

Default

300

Protocols

All

Example

CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
 
  /* complete connection within 10 seconds */
  curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 10L);
 
  curl_easy_perform(curl);
}

Availability

Always

Return value

Returns CURLE_OK. Returns CURLE_BAD_FUNCTION_ARGUMENT if set to a negative value or a value that when converted to milliseconds is too large.