php cURL progress function size limit

Question

I'm downloading a file using cURL 7.38.0 with php 5.6 and I'd like to get the download progress. This is my code:

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, "http://path/to/file.zip");
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_BUFFERSIZE, 65536);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, 'downloadProgress'); 
curl_setopt($ch, CURLOPT_NOPROGRESS, false);

curl_exec($ch);
curl_close($ch);

function downloadProgress ($resource, $download_size, $downloaded_size, $upload_size, $uploaded_size) {
    echo 'download_size: ' . $download_size . '; downloaded_size: ' . $downloaded_size . ';<br>';
}

Everything works fine most of the time except that if the file is bigger than 2GB, then $download_size returns -2147483648 and $downloaded_size works until it gets to 2147483648 and also turns to -2147483648 and stops incrementing.

The output with a 3.4GB file is the following:

download_size: 0; downloaded_size: 0;
download_size: -2147483648; downloaded_size: 1147;
download_size: -2147483648; downloaded_size: 1147;
download_size: -2147483648; downloaded_size: 16987;
download_size: -2147483648; downloaded_size: 16987;
download_size: -2147483648; downloaded_size: 25627;
...
download_size: -2147483648; downloaded_size: -2147483648;
download_size: -2147483648; downloaded_size: -2147483648;
download_size: -2147483648; downloaded_size: -2147483648;

Is there something I have done wrong or is it a php cURL limitation?

Thank you.

Answer 1

CURLOPT_PROGRESSFUNCTION function argument type are double, so you are probably casting these value to int somewhere in your code. and probably since your os is 32bit based architecture you are overflowing the int size limit. I would suggest you revise your code to avoid casting to int big double numbers.