I have the need to abort a curl_easy_perform() instantly, or close to
it, at any time during it's operation, whether connecting, transferring,
or waiting for a timeout.

I have seen this a lot on the mailing list, and as far as I know this is
still not an available feature. Is this true?

 From what I have read, the suggestion has been to return an error from
within a callback. However, there are times (such as waiting for a
connection) when no callback is called. This is, I believe, a fairly
typical situation. I have a multi-threaded program, and one of the
threads is initiating or executing a transfer. Other threads, oblivious
to this, may be operating a control panel or some other UI component
which, at the user's whim, may be clicked and cause the chosen transfer
to immediately terminate. I can't have the user "waiting" for this. It
needs to be instant.

I am going to implement some method of doing this and send a patch.
However, I wanted to be SURE that nobody else is implementing the same
thing, or that there is no better way before I spend the time doing so.

My method will be to create a new curl_easy_setopt called
CURLOPT_ABORTFLAG, which is called like this:

    volatile long abort_flag = 0;
    curl_easy_setopt(curlhandle, CURLOPT_ABORTFLAG, (long)&abort_flag);

At any time, any asynchronous thread can set abort flag to 1 in order to
cause CURL to abort the current operation.

Is this reasonable?

-G
Received on 2005-08-22