1curl_easy_recv(3)               libcurl Manual               curl_easy_recv(3)
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NAME

6       curl_easy_recv - receives raw data on an "easy" connection
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SYNOPSIS

9       #include <curl/easy.h>
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11       CURLcode  curl_easy_recv(  CURL  *curl,  void  *buffer,  size_t buflen,
12       size_t *n);
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DESCRIPTION

15       This function receives raw data from the  established  connection.  You
16       may  use  it together with curl_easy_send(3) to implement custom proto‐
17       cols using libcurl. This functionality can be  particularly  useful  if
18       you  use proxies and/or SSL encryption: libcurl will take care of proxy
19       negotiation and connection set-up.
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21       buffer is a pointer to your buffer that will  get  the  received  data.
22       buflen  is  the  maximum amount of data you can get in that buffer. The
23       variable n points to will receive the number of received bytes.
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25       To establish the connection, set CURLOPT_CONNECT_ONLY(3) option  before
26       calling   curl_easy_perform(3)   or  curl_multi_perform(3).  Note  that
27       curl_easy_recv(3) does not work on connections that were created  with‐
28       out this option.
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30       The  call  will  return  CURLE_AGAIN  if there is no data to read - the
31       socket is used in non-blocking mode  internally.  When  CURLE_AGAIN  is
32       returned,  use  your operating system facilities like select(2) to wait
33       for data. The socket may be obtained  using  curl_easy_getinfo(3)  with
34       CURLINFO_ACTIVESOCKET(3).
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36       Wait  on the socket only if curl_easy_recv(3) returns CURLE_AGAIN.  The
37       reason for this is libcurl or the SSL library may internally cache some
38       data,  therefore  you  should  call curl_easy_recv(3) until all data is
39       read which would include any cached data.
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41       Furthermore if you wait on the socket and it tells you there is data to
42       read,  curl_easy_recv(3)  may  return CURLE_AGAIN if the only data that
43       was read was for internal SSL processing, and no other data  is  avail‐
44       able.
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AVAILABILITY

48       Added in 7.18.2.
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RETURN VALUE

51       On success, returns CURLE_OK, stores the received data into buffer, and
52       the number of bytes it actually read into *n.
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54       On failure, returns the appropriate error code.
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56       The function may return CURLE_AGAIN. In this case, use  your  operating
57       system facilities to wait until data can be read, and retry.
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59       Reading exactly 0 bytes indicates a closed connection.
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61       If  there's no socket available to use from the previous transfer, this
62       function returns CURLE_UNSUPPORTED_PROTOCOL.
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EXAMPLE

65       See sendrecv.c in docs/examples directory for usage example.
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SEE ALSO

68       curl_easy_setopt(3),    curl_easy_perform(3),     curl_easy_getinfo(3),
69       curl_easy_send(3)
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73libcurl 7.69.1                 December 18, 2016             curl_easy_recv(3)
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