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Re: functionality of sockfd of curl_multi_socket_action

From: Pahome Chen via curl-library <curl-library_at_cool.haxx.se>
Date: Wed, 10 May 2017 13:07:14 +0800

So libcurl use the socket for get data if ev_bitmask is IN
send request out if ev_bitmask is OUT ?

2017-05-05 19:46 GMT+08:00 Daniel Stenberg <daniel_at_haxx.se>:

> On Fri, 5 May 2017, Pahome Chen via curl-library wrote:
>
> curl_multi_socket_action(CURLM * multi_handle,
>> *curl_socket_t sockfd*,
>> int ev_bitmask,
>> int *running_handles);
>>
>> It always said that we can set to the socket *sockfd *with *action*, it
>> doesn't mentioned what's the functionality of *sockfd *in the function.That
>> makes me confused.
>>
>
> It is mentioned in several places in the documentation, and I've explained
> it in previous replies. But let me try again.
>
> curl_multi_socket_action is part of the multi_socket API. It is an
> event-based API. It assumes that you use an event-based library or
> underlying system that tells you when there's activity/action on one of the
> sockets/file descriptors you've asked it to monitor.
>
> When you use curl_multi_socket_action(), you get told by libcurl which
> file descriptors to wait for and for what particular activity on that
> socket. You should then set that information in your event-based library.
>
> Then, when your event-lib tells you there actually is actitity on the
> socket that it monitors on the behalf of libcurl, it probably calls a
> callback you have provided for it.
>
> You then call curl_multi_socket_action() to tell libcurl about which
> socket that got action and what particular action it was that was detected.
> That socket is the 'sockfd' argument to curl_multi_socket_action() and
> 'ev_bitmask' is what activity/events that happened on the socket.
>
> --
>
> / daniel.haxx.se
>

-- 
Best Regards,
pahome

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Received on 2017-05-10