---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_CONNECTTIMEOUT_MS
Section: 3
Source: libcurl
See-also:
  - CURLOPT_LOW_SPEED_LIMIT (3)
  - CURLOPT_MAX_RECV_SPEED_LARGE (3)
  - CURLOPT_TIMEOUT_MS (3)
Protocol:
  - All
Added-in: 7.16.2
---

# NAME

CURLOPT_CONNECTTIMEOUT_MS - timeout for the connect phase

# SYNOPSIS

~~~c
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CONNECTTIMEOUT_MS,
                          long timeout);
~~~

# DESCRIPTION

Pass a long. It sets the maximum time in milliseconds that you allow the
connection phase to take. This timeout only limits the connection phase, it
has no impact once libcurl has connected. The connection phase includes the
name resolve (DNS) and all protocol handshakes and negotiations until there is
an established connection with the remote side.

Set this option to zero to switch to the default built-in connection timeout -
300 seconds. See also the CURLOPT_TIMEOUT_MS(3) option.

CURLOPT_CONNECTTIMEOUT(3) is the same function but set in seconds.

If both CURLOPT_CONNECTTIMEOUT(3) and CURLOPT_CONNECTTIMEOUT_MS(3) are set,
the value set last is used.

The connection timeout is included in the general all-covering
CURLOPT_TIMEOUT_MS(3):

With CURLOPT_CONNECTTIMEOUT_MS(3) set to 3000 and CURLOPT_TIMEOUT_MS(3) set to
5000, the operation can never last longer than 5000 milliseconds, and the
connection phase cannot last longer than 3000 milliseconds.

With CURLOPT_CONNECTTIMEOUT_MS(3) set to 4000 and CURLOPT_TIMEOUT_MS(3) set to
2000, the operation can never last longer than 2000 milliseconds. 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(3) is set.

# DEFAULT

300000

# %PROTOCOLS%

# EXAMPLE

~~~c
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    /* complete connection within 10000 milliseconds */
    curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT_MS, 10000L);

    curl_easy_perform(curl);
  }
}
~~~

# %AVAILABILITY%

# RETURN VALUE

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
libcurl-errors(3).
