Unknown option: "-3" Unix manual page for CURLOPT_TCP_KEEPIDLE. (host=minya system=Darwin)
CURLOPT_TCP_KEEPIDLE(3)    curl_easy_setopt options    CURLOPT_TCP_KEEPIDLE(3)

NAME
       CURLOPT_TCP_KEEPIDLE - set TCP keep-alive idle time wait

SYNOPSIS
       #include <curl/curl.h>

       CURLcode   curl_easy_setopt(CURL  *handle,  CURLOPT_TCP_KEEPIDLE,  long
       delay);

DESCRIPTION
       Pass a long. Sets the delay, in seconds, that the operating system will
       wait  while the connection is idle before sending keepalive probes. Not
       all operating systems support this option.

DEFAULT
       60

PROTOCOLS
       All

EXAMPLE
       CURL *curl = curl_easy_init();
       if(curl) {
         curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");

         /* enable TCP keep-alive for this transfer */
         curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);

         /* set keep-alive idle time to 120 seconds */
         curl_easy_setopt(curl, CURLOPT_TCP_KEEPIDLE, 120L);

         /* interval time between keep-alive probes: 60 seconds */
         curl_easy_setopt(curl, CURLOPT_TCP_KEEPINTVL, 60L);

         curl_easy_perform(curl);
       }

AVAILABILITY
       Added in 7.25.0

RETURN VALUE
       Returns CURLE_OK if the option is supported,  and  CURLE_UNKNOWN_OPTION
       if not.

SEE ALSO
       CURLOPT_TCP_KEEPALIVE(3), CURLOPT_TCP_KEEPINTVL(3),

libcurl 7.54.0                 January 02, 2017        CURLOPT_TCP_KEEPIDLE(3)