mirror of
https://github.com/moparisthebest/curl
synced 2024-11-05 00:55:04 -05:00
afff64dbcd
Follow-up to 82245ea: Fix the example program sendrecv.c (handle
CURLE_AGAIN, handle incomplete send). Improve the documentation
for curl_easy_recv() and curl_easy_send().
Reviewed-by: Frank Meier
Assisted-by: Jay Satiro
See https://github.com/curl/curl/pull/1134
85 lines
3.7 KiB
Groff
85 lines
3.7 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * 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_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 \fICURLOPT_CONNECT_ONLY(3)\fP option before
|
|
calling \fIcurl_easy_perform(3)\fP or \fIcurl_multi_perform(3)\fP. Note that
|
|
\fIcurl_easy_recv(3)\fP does not work on connections that were created without
|
|
this option.
|
|
|
|
The call will return \fBCURLE_AGAIN\fP if there is no data to read - the
|
|
socket is used in non-blocking mode internally. When \fBCURLE_AGAIN\fP is
|
|
returned, use your operating system facilities like \fIselect(2)\fP to wait
|
|
for data. The socket may be obtained using \fIcurl_easy_getinfo(3)\fP with
|
|
\fICURLINFO_ACTIVESOCKET(3)\fP.
|
|
|
|
Wait on the socket only if \fIcurl_easy_recv(3)\fP returns \fBCURLE_AGAIN\fP.
|
|
The reason for this is libcurl or the SSL library may internally cache some
|
|
data, therefore you should call \fIcurl_easy_recv(3)\fP until all data is
|
|
read which would include any cached data.
|
|
|
|
Furthermore if you wait on the socket and it tells you there is data to read,
|
|
\fIcurl_easy_recv(3)\fP may return \fBCURLE_AGAIN\fP if the only data that was
|
|
read was for internal SSL processing, and no other data is available.
|
|
|
|
.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.
|
|
|
|
The function may return \fBCURLE_AGAIN\fP. In this case, use your operating
|
|
system facilities to wait until data can be read, and retry.
|
|
|
|
Reading exactly 0 bytes indicates a closed connection.
|
|
|
|
If there's no socket available to use from the previous transfer, this function
|
|
returns \fBCURLE_UNSUPPORTED_PROTOCOL\fP.
|
|
.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) "
|