a718cb05ff
now to enable them to get added as web pages easier, they are not ready for anything "real" just yet.
83 lines
3.6 KiB
Groff
83 lines
3.6 KiB
Groff
.\" $Id$
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.\"
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.TH curl_multi_socket 3 "21 Dec 2005" "libcurl 7.16.0" "libcurl Manual"
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.SH NAME
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curl_multi_socket - reads/writes available data
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.SH SYNOPSIS
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#include <curl/curl.h>
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CURLMcode curl_multi_socket(CURLM * multi_handle,
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curl_socket_t sockfd,
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CURL *easy,
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curl_socket_callback callback,
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void *userp);
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CURLMcode curl_multi_socket_all(CURLM *multi_handle,
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curl_socket_callback callback,
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void *userp);
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.SH DESCRIPTION
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Alternative versions of \fIcurl_multi_perform()\fP that allows the application
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to pass in one of the file descriptors/sockets that have been detected to have
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\&"action" on them and let libcurl perform. This allows libcurl to not have to
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scan through all possible file descriptors to check for action. The
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application is recommended to pass in the \fBeasy\fP argument (or set it to
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CURL_EASY_NONE) to make libcurl figure out the internal structure even faster
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and easier. If the easy argument is set to something else than
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CURL_EASY_NONE, the \fBsockfd\fP argument will be ignored by libcurl.
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These functions inform the application about updates in the socket (file
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descriptor) status by doing none, one or multiple calls to the
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curl_socket_callback given in the \fBcallback\fP argument. They update the
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status with changes since the previous time this function was used. If
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\fBcallback\fP is NULL, no callback will be called. A status change may also
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be a new timeout only, having the same IN/OUT status as before.
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If a previous wait for socket action(s) timed out, you should call this
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function with the socket argument set to CURL_SOCKET_TIMEOUT. If you want to
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force libcurl to (re-)check all its internal sockets, and call the callback
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with status for all sockets no matter what the previous state is, you call
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curl_multi_socket_all() instead.
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curl_multi_perform() is the equivalent of calling
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curl_multi_socket_all(handle, NULL, NULL);
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Regarding the timeout argument in the callback: it is the timeout (in
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milliseconds) for waiting on action on this socket (and the given time period
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starts when the callback is called) until you should call curl_multi_socket()
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with the timeout stuff mentioned above. If "actions" happens on the socket
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before the timeout happens, remember that the timout timer keeps ticking until
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told otherwise.
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The "what" argument has one of five values:
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.RS
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.IP "CURL_POLL_NONE (0)"
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register, not interested in readiness (yet)
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.IP "CURL_POLL_IN (1)"
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register, interested in read readiness
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.IP "CURL_POLL_OUT (2)"
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register, interested in write readiness
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.IP "CURL_POLL_INOUT (3)"
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register, interested in both read and write readiness
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.IP "CURL_POLL_REMOVE (4)"
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deregister
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.RE
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.SH "RETURN VALUE"
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CURLMcode type, general libcurl multi interface error code.
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If you receive \fICURLM_CALL_MULTI_PERFORM\fP, this basically means that you
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should call \fIcurl_multi_perform\fP again, before you select() on more
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actions. You don't have to do it immediately, but the return code means that
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libcurl may have more data available to return or that there may be more data
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to send off before it is "satisfied".
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NOTE that this only returns errors etc regarding the whole multi stack. There
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might still have occurred problems on individual transfers even when this
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function returns OK.
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.SH "TYPICAL USAGE"
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Call curl_multi_socket_all() first. Setup a "collection" of sockets to
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supervise, then when action happens call curl_multi_socket() for the easy
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handle that got the action.
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.SH "SEE ALSO"
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.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
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.BR curl_multi_fdset "(3), " curl_multi_info_read "(3)"
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