oracular (3) curl_easy_send.3.gz

NAME

       curl_easy_send - sends raw data over an "easy" connection

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_send(CURL *curl, const void *buffer,
                               size_t buflen, size_t *n);

DESCRIPTION

       This  function  sends  arbitrary  data  over  the  established  connection.  You may use it together with
       curl_easy_recv(3) to implement custom protocols using libcurl. This  functionality  can  be  particularly
       useful  if  you use proxies and/or SSL encryption: libcurl takes care of proxy negotiation and connection
       setup.

       buffer is a pointer to the data of length buflen that you want sent. The variable n  points  to  receives
       the number of sent bytes.

       To  establish  the  connection, set CURLOPT_CONNECT_ONLY(3) option before calling curl_easy_perform(3) or
       curl_multi_perform(3). Note that curl_easy_send(3) does not work on connections that were created without
       this option.

       The  call  returns  CURLE_AGAIN  if  it  is  not  possible to send data right now - the socket is used in
       non-blocking mode internally. When CURLE_AGAIN is returned, use your  operating  system  facilities  like
       select(2)  to  wait  until  the socket is writable. The socket may be obtained using curl_easy_getinfo(3)
       with CURLINFO_ACTIVESOCKET(3).

       Furthermore if you wait on the socket and it tells you  it  is  writable,  curl_easy_send(3)  may  return
       CURLE_AGAIN  if  the  only data that was sent was for internal SSL processing, and no other data could be
       sent.

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");
           /* Do not do the transfer - only connect to host */
           curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1L);
           res = curl_easy_perform(curl);

           if(res == CURLE_OK) {
             long sockfd;
             size_t sent;
             /* Extract the socket from the curl handle - we need it for waiting. */
             res = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd);

             /* send data */
             res = curl_easy_send(curl, "hello", 5, &sent);
           }
         }
       }

AVAILABILITY

       Added in curl 7.18.2

RETURN VALUE

       On success, returns CURLE_OK and stores the number of bytes actually sent into *n. Note that this may  be
       less than the amount you wanted to send.

       On failure, returns the appropriate error code.

       This  function  may  return CURLE_AGAIN. In this case, use your operating system facilities to wait until
       the socket is writable, and retry.

       If  there  is  no  socket  available  to  use  from  the  previous  transfer,   this   function   returns
       CURLE_UNSUPPORTED_PROTOCOL.

SEE ALSO

       curl_easy_getinfo(3), curl_easy_perform(3), curl_easy_recv(3), curl_easy_setopt(3)