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                     23: .TH curl_easy_recv 3 "December 18, 2016" "libcurl 7.70.0" "libcurl Manual"
                     24: 
                     25: .SH NAME
                     26: curl_easy_recv - receives raw data on an "easy" connection
                     27: .SH SYNOPSIS
                     28: .B #include <curl/easy.h>
                     29: .sp
                     30: .BI "CURLcode curl_easy_recv( CURL *" curl ", void *" buffer ","
                     31: .BI "size_t " buflen ", size_t *" n ");"
                     32: .ad
                     33: .SH DESCRIPTION
                     34: This function receives raw data from the established connection. You may use
                     35: it together with \fIcurl_easy_send(3)\fP to implement custom protocols using
                     36: libcurl. This functionality can be particularly useful if you use proxies
                     37: and/or SSL encryption: libcurl will take care of proxy negotiation and
                     38: connection set-up.
                     39: 
                     40: \fBbuffer\fP is a pointer to your buffer that will get the received
                     41: data. \fBbuflen\fP is the maximum amount of data you can get in that
                     42: buffer. The variable \fBn\fP points to will receive the number of received
                     43: bytes.
                     44: 
                     45: To establish the connection, set \fICURLOPT_CONNECT_ONLY(3)\fP option before
                     46: calling \fIcurl_easy_perform(3)\fP or \fIcurl_multi_perform(3)\fP. Note that
                     47: \fIcurl_easy_recv(3)\fP does not work on connections that were created without
                     48: this option.
                     49: 
                     50: The call will return \fBCURLE_AGAIN\fP if there is no data to read - the
                     51: socket is used in non-blocking mode internally. When \fBCURLE_AGAIN\fP is
                     52: returned, use your operating system facilities like \fIselect(2)\fP to wait
                     53: for data. The socket may be obtained using \fIcurl_easy_getinfo(3)\fP with
                     54: \fICURLINFO_ACTIVESOCKET(3)\fP.
                     55: 
                     56: Wait on the socket only if \fIcurl_easy_recv(3)\fP returns \fBCURLE_AGAIN\fP.
                     57: The reason for this is libcurl or the SSL library may internally cache some
                     58: data, therefore you should call \fIcurl_easy_recv(3)\fP until all data is
                     59: read which would include any cached data.
                     60: 
                     61: Furthermore if you wait on the socket and it tells you there is data to read,
                     62: \fIcurl_easy_recv(3)\fP may return \fBCURLE_AGAIN\fP if the only data that was
                     63: read was for internal SSL processing, and no other data is available.
                     64: 
                     65: .SH AVAILABILITY
                     66: Added in 7.18.2.
                     67: .SH RETURN VALUE
                     68: On success, returns \fBCURLE_OK\fP, stores the received data into
                     69: \fBbuffer\fP, and the number of bytes it actually read into \fB*n\fP.
                     70: 
                     71: On failure, returns the appropriate error code.
                     72: 
                     73: The function may return \fBCURLE_AGAIN\fP. In this case, use your operating
                     74: system facilities to wait until data can be read, and retry.
                     75: 
                     76: Reading exactly 0 bytes indicates a closed connection.
                     77: 
                     78: If there's no socket available to use from the previous transfer, this function
                     79: returns \fBCURLE_UNSUPPORTED_PROTOCOL\fP.
                     80: .SH EXAMPLE
                     81: See \fBsendrecv.c\fP in \fBdocs/examples\fP directory for usage example.
                     82: .SH "SEE ALSO"
                     83: .BR curl_easy_setopt "(3), " curl_easy_perform "(3), "
                     84: .BR curl_easy_getinfo "(3), "
                     85: .BR curl_easy_send "(3) "