> On 12 Jul 2010, at 12:18 PM, Daniel Stenberg wrote:
> Possibly it could be made as another callback: getbuffer()
>
> getbuffer() gets called when libcurl needs a new buffer, and the buffer you
> provide to libcurl with that callback must be able to hold at least
> CURL_MAX_WRITE_SIZE bytes. When libcurl calls the write callback, it will
> pass on a pointer to within that buffer and a length. Note that it MAY not
> point to the first byte of the passed-in buffer.

I see a problem here, in that CURL_MAX_WRITE_SIZE is defined at compile time,
yet the application could be linked at run time to a libcurl that used a
different value. If libcurl's value were greater, then it will overwrite
the end of the buffer passed in.

What is probably needed is a curl_easy_getinfo analog to the curl_easy_setopt
option CURLOPT_BUFFERSIZE to query at run time what size is expected, or just
force the zero copy interface user to set CURLOPT_BUFFERSIZE at least once
before supplying a buffer.

>>> Dan
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Received on 2010-07-19