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Re: cURL Write Data Buffer size

From: Ray Satiro via curl-library <>
Date: Thu, 16 Mar 2017 15:40:46 -0400

On 3/16/2017 3:16 PM, doa379 wrote:
> I'm using the API to fetch data and am using the WRITEDATA,
> WRITEFUNCTION options to handle it. Unfortunately I am finding that in
> some instances where the data is too long it gets separated in more
> than one call of the WRITEFUNCTION callback function. At this point
> the application loses track of the data because I am using the API to
> fetch other URLs as well. Is there any way to control the size of the
> buffer so that all of the data can be handled in a single call of
> An earlier approach that I tried was to have predefined slots for each
> of the URLs (tracks of data). In which case each of the slots got
> populated with data at leisure over multiple calls of the
> WRITEFUNCTION. This works but there's some drawback in efficiency and
> this implementation faces some other symptomatic inadequacies with the
> I have now decided to use a single WRITEDATA buffer. But I wish to set
> or increase its size so that WRITEFUNCTION need only be called a
> single time for any given track of data or URL.

No, there's no guarantee of how many times the write function will be
called regardless of the data size. If you are doing multiple transfers
in parallel using multi you'll need to account for that, in your case I
suspect by using separate buffers.

Received on 2017-03-16