curl/docs/libcurl/curl_easy_send.3

.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.haxx.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" **************************************************************************
.\"
.TH curl_easy_send 3 "29 April 2008" "libcurl 7.18.2" "libcurl Manual"
.SH NAME
curl_easy_send - sends raw data over an "easy" connection
.SH SYNOPSIS
.B #include <curl/easy.h>
.sp
.BI "CURLcode curl_easy_send( CURL *" curl ", const void *" buffer ","
.BI " size_t " buflen ", size_t *" n ");"
.ad
.SH DESCRIPTION
This function sends arbitrary data over the established connection. You may
use it together with \fIcurl_easy_recv(3)\fP 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 set-up.

\fBbuffer\fP is a pointer to the data of length \fBbuflen\fP that you want sent.
The variable \fBn\fP points to will receive the number of sent bytes.

To establish the connection, set \fICURLOPT_CONNECT_ONLY(3)\fP option before
calling \fIcurl_easy_perform(3)\fP or \fIcurl_multi_perform()\fP. Note that
\fIcurl_easy_send(3)\fP will not work on connections that were created without
this option.

You must ensure that the socket is writable before calling
\fIcurl_easy_send(3)\fP, otherwise the call will return \fBCURLE_AGAIN\fP -
the socket is used in non-blocking mode internally. Use
\fIcurl_easy_getinfo(3)\fP with \fICURLINFO_ACTIVESOCKET(3)\fP to obtain the
socket; use your operating system facilities like \fIselect(2)\fP to check if
it can be written to.
.SH AVAILABILITY
Added in 7.18.2.
.SH RETURN VALUE
On success, returns \fBCURLE_OK\fP and stores the number of bytes actually
sent into \fB*n\fP. Note that this may very well be less than the amount you
wanted to send.

On failure, returns the appropriate error code.

If there's no socket available to use from the previous transfer, this function
returns CURLE_UNSUPPORTED_PROTOCOL.
.SH EXAMPLE
See \fBsendrecv.c\fP in \fBdocs/examples\fP directory for usage example.
.SH "SEE ALSO"
.BR curl_easy_setopt "(3), " curl_easy_perform "(3), " curl_easy_getinfo "(3), "
.BR curl_easy_recv "(3) "