CURLOPT_LOCALPORT(3)       Library Functions Manual       CURLOPT_LOCALPORT(3)

NAME
       CURLOPT_LOCALPORT - local port number to use for socket

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_LOCALPORT, long port);

DESCRIPTION
       Pass a long. This sets the local port number of the socket used for the
       connection. This can be used in combination with CURLOPT_INTERFACE(3)
       and you are recommended to use CURLOPT_LOCALPORTRANGE(3) as well when
       this option is set. Valid port numbers are 1 - 65535.

DEFAULT
       0, disabled - use whatever the system thinks is fine

PROTOCOLS
       This functionality affects all supported protocols

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 curl 7.15.2

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).

SEE ALSO
       CURLINFO_LOCAL_PORT(3), CURLOPT_INTERFACE(3), CURLOPT_LOCALPORTRANGE(3)

libcurl                           2025-02-13              CURLOPT_LOCALPORT(3)