CURLOPT_LOCALPORTRANGE(3)  Library Functions Manual  CURLOPT_LOCALPORTRANGE(3)

NAME
       CURLOPT_LOCALPORTRANGE - number of additional local ports to try

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_LOCALPORTRANGE,
                                 long range);

DESCRIPTION
       Pass a long. The range argument is the number of attempts libcurl makes
       to find a working local port number. It starts with the given
       CURLOPT_LOCALPORT(3) and adds one to the number for each retry. Setting
       this option to 1 or below makes libcurl only do one try for the exact
       port number. Port numbers by nature are scarce resources that are busy
       at times so setting this value to something too low might cause
       unnecessary connection setup failures.

DEFAULT
       1

PROTOCOLS
       All

EXAMPLE
       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           CURLcode res;
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
           curl_easy_setopt(curl, CURLOPT_LOCALPORT, 49152L);
           /* and try 20 more ports following that */
           curl_easy_setopt(curl, CURLOPT_LOCALPORTRANGE, 20L);
           res = curl_easy_perform(curl);
           curl_easy_cleanup(curl);
         }
       }

AVAILABILITY
       Added in 7.15.2

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

SEE ALSO
       CURLOPT_INTERFACE(3), CURLOPT_LOCALPORT(3)

libcurl                          April 26 2024       CURLOPT_LOCALPORTRANGE(3)