mojave man page for curlopt_sockoptfunction

CURLOPT_SOCKOPTFUNCTION(3)				     curl_easy_setopt options					CURLOPT_SOCKOPTFUNCTION(3)

NAME
       CURLOPT_SOCKOPTFUNCTION - set callback for setting socket options

SYNOPSIS
       #include <curl/curl.h>

       typedef enum  {
	 CURLSOCKTYPE_IPCXN,  /* socket created for a specific IP connection */
	 CURLSOCKTYPE_ACCEPT, /* socket created by accept() call */
	 CURLSOCKTYPE_LAST    /* never use */
       } curlsocktype;

       #define CURL_SOCKOPT_OK 0
       #define CURL_SOCKOPT_ERROR 1 /* causes libcurl to abort and return
				       CURLE_ABORTED_BY_CALLBACK */
       #define CURL_SOCKOPT_ALREADY_CONNECTED 2

       int sockopt_callback(void *clientp,
			    curl_socket_t curlfd,
			    curlsocktype purpose);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);

DESCRIPTION
       Pass a pointer to your callback function, which should match the prototype shown above.

       When set, this callback function gets called by libcurl when the socket has been created, but before the connect call to allow applications
       to change specific socket options. The callback's purpose argument identifies the exact purpose for this particular socket:

       CURLSOCKTYPE_IPCXN for actively created connections or since 7.28.0  CURLSOCKTYPE_ACCEPT  for  FTP  when  the  connection  was  setup  with
       PORT/EPSV (in earlier versions these sockets weren't passed to this callback).

       Future  versions  of  libcurl  may  support more purposes. libcurl passes the newly created socket descriptor to the callback in the curlfd
       parameter so additional setsockopt() calls can be done at the user's discretion.

       The clientp pointer contains whatever user-defined value set using the CURLOPT_SOCKOPTDATA(3) function.

       Return CURL_SOCKOPT_OK from the callback on success. Return CURL_SOCKOPT_ERROR from the callback function to signal an unrecoverable  error
       to  the	library and it will close the socket and return CURLE_COULDNT_CONNECT.	Alternatively, the callback function can return CURL_SOCK-
       OPT_ALREADY_CONNECTED, to tell libcurl that the socket is already connected and then libcurl will not attempt to connect it. This allows an
       application  to pass in an already connected socket with CURLOPT_OPENSOCKETFUNCTION(3) and then have this function make libcurl not attempt
       to connect (again).

DEFAULT
       By default, this callback is NULL and unused.

PROTOCOLS
       All

EXAMPLE
       TODO

AVAILABILITY
       Added in 7.16.0. The CURL_SOCKOPT_ALREADY_CONNECTED return code was added in 7.21.5.

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

SEE ALSO
       CURLOPT_SOCKOPTDATA(3), CURLOPT_OPENSOCKETFUNCTION(3),

libcurl 7.54.0							 February 03, 2016					CURLOPT_SOCKOPTFUNCTION(3)