curl_easy_send - sends raw data over an "easy" connection
#include <curl/easy.h>
CURLcode curl_easy_send(CURL *curl, const void *buffer,
size_t buflen, size_t *n);
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 will take 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 will receive 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
will not work on connections that were created
without this option.
The call will return
CURLE_AGAIN if it's 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's writable,
may return
CURLE_AGAIN if the only data that
was sent was for internal SSL processing, and no other data could be sent.
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) {
/* Extract the socket from the curl handle -
we will need it for waiting. */
res = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd);
/* send data */
res = curl_easy_send(curl, "hello", 5, &sent);
}
Added in 7.18.2.
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's no socket available to use from the previous transfer, this function
returns
CURLE_UNSUPPORTED_PROTOCOL.
curl_easy_setopt(3),
curl_easy_perform(3),
curl_easy_getinfo(3),
curl_easy_recv(3)