plucky (3) CURLOPT_INTERFACE.3.gz

NAME

       CURLOPT_INTERFACE - source interface for outgoing traffic

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_INTERFACE, char *interface);

DESCRIPTION

       Pass  a char pointer as parameter. This sets the interface name to use as outgoing network interface. The
       name can be an interface name, an IP address, or a hostname. If you prefer one of these, you can use  the
       following special prefixes:

       *  if!<name>  -  Interface  name  *  host!<name>  -  IP address or hostname * ifhost!<interface>!<host> -
       Interface name and IP address or hostname

       If  if!  or  ifhost!  is  specified  but  the  parameter  does   not   match   an   existing   interface,
       CURLE_INTERFACE_FAILED is returned from the libcurl function used to perform the transfer.

       libcurl does not support using network interface names for this option on Windows.

       We  strongly  advise  against  specifying  the  interface  with  a hostname, as it causes libcurl to do a
       blocking name resolve call to retrieve the  IP  address.   That  name  resolve  operation  does  not  use
       DNS-over-HTTPS even if CURLOPT_DOH_URL(3) is set.

       The application does not have to keep the string around after setting this option.

       Using  this option multiple times makes the last set string override the previous ones. Set it to NULL to
       disable its use again.

DEFAULT

       NULL, use whatever the TCP stack finds suitable

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_INTERFACE, "eth0");

           res = curl_easy_perform(curl);

           curl_easy_cleanup(curl);
         }
       }

HISTORY

       The if! and host! syntax was added in 7.24.0.

       The ifhost! syntax was added in 8.9.0.

AVAILABILITY

       Added in curl 7.3

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

       CURLOPT_LOCALPORT(3), CURLOPT_SOCKOPTFUNCTION(3), CURLOPT_TCP_NODELAY(3)