curl/docs/libcurl/curl_easy_recv.3

.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2015, 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 http://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_recv 3 "29 April 2008" "libcurl 7.18.2" "libcurl Manual"
.SH NAME
curl_easy_recv - receives raw data on an "easy" connection
.SH SYNOPSIS
.B #include <curl/easy.h>
.sp
.BI "CURLcode curl_easy_recv( CURL *" curl ", void *" buffer ","
.BI "size_t " buflen ", size_t *" n ");"
.ad
.SH DESCRIPTION
This function receives raw data from the established connection. You may use
it together with \fIcurl_easy_send(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 your buffer that will get the received
data. \fBbuflen\fP is the maximum amount of data you can get in that
buffer. The variable \fBn\fP points to will receive the number of received
bytes.

To establish the connection, set \fBCURLOPT_CONNECT_ONLY(3)\fP option before
calling \fIcurl_easy_perform(3)\fP or \cIcurl_multi_perform(3)\fP. Note that
\fIcurl_easy_recv(3)\fP does not work on connections that were created without
this option.

You must ensure that the socket has data to read before calling
\fIcurl_easy_recv(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 \fBCURLINFO_LASTSOCKET\fP to obtain the
socket; use your operating system facilities like \fIselect(2)\fP to check if
it has any data you can read.
.SH AVAILABILITY
Added in 7.18.2.
.SH RETURN VALUE
On success, returns \fBCURLE_OK\fP, stores the received data into
\fBbuffer\fP, and the number of bytes it actually read into \fB*n\fP.

On failure, returns the appropriate error code.

If there is no data to read, the function returns \fBCURLE_AGAIN\fP. Use your
operating system facilities to wait until the data is ready, and retry.

Reading exactly 0 bytes would indicate a closed connection.

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), "
.BR curl_easy_getinfo "(3), "
.BR curl_easy_send "(3) "