From afff64dbcde9cf45956f5557a8270b21c0e93dd5 Mon Sep 17 00:00:00 2001 From: Michael Kaufmann Date: Sun, 18 Dec 2016 12:51:48 +0100 Subject: curl_easy_recv: Improve documentation and example program 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 --- docs/libcurl/curl_easy_send.3 | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) (limited to 'docs/libcurl/curl_easy_send.3') diff --git a/docs/libcurl/curl_easy_send.3 b/docs/libcurl/curl_easy_send.3 index 2a7443985..47976f391 100644 --- a/docs/libcurl/curl_easy_send.3 +++ b/docs/libcurl/curl_easy_send.3 @@ -40,16 +40,20 @@ connection set-up. 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 +calling \fIcurl_easy_perform(3)\fP or \fIcurl_multi_perform(3)\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. +The call will return \fBCURLE_AGAIN\fP if it's not possible to send data right +now - 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 until the socket is writable. The socket may be +obtained using \fIcurl_easy_getinfo(3)\fP with \fICURLINFO_ACTIVESOCKET(3)\fP. + +Furthermore if you wait on the socket and it tells you it's writable, +\fIcurl_easy_send(3)\fP may return \fBCURLE_AGAIN\fP if the only data that was +sent was for internal SSL processing, and no other data could be sent. + .SH AVAILABILITY Added in 7.18.2. .SH RETURN VALUE @@ -59,8 +63,11 @@ wanted to send. On failure, returns the appropriate error code. +This function may return \fBCURLE_AGAIN\fP. In this case, use your operating +system facilities to wait until the socket is writable, and retry. + If there's no socket available to use from the previous transfer, this function -returns CURLE_UNSUPPORTED_PROTOCOL. +returns \fBCURLE_UNSUPPORTED_PROTOCOL\fP. .SH EXAMPLE See \fBsendrecv.c\fP in \fBdocs/examples\fP directory for usage example. .SH "SEE ALSO" -- cgit v1.2.3