php curl module ignores proxychains

try this simple script:

<?php
echo "file_get_contents:\n";
echo file_get_contents("http://ifconfig.me/ip");
echo "curl:\n";
$ch=curl_init();
curl_setopt($ch,CURLOPT_URL,"http://ifconfig.me/ip");
curl_setopt($ch,CURLOPT_HEADER,0);
curl_exec($ch);
curl_close($ch);

assume that my real ip is 123.45.67.89 and socks proxy ip is 10.10.10.10
without proxychains:

# php php_curl.php 
file_get_contents:
123.45.67.89
curl:
123.45.67.89

with proxychains:

# proxychains php php_curl.php 
[proxychains] config file found: /etc/proxychains.conf
[proxychains] preloading /usr/lib/libproxychains4.so
file_get_contents:
10.10.10.10
curl:
123.45.67.89

i.e. curl was not proxified even with proxychains library preloaded.

Start by running the php_curl.php script with and without proxychains, using the /etc/proxychains.conf configuration and the preloaded libproxychains4.so shown in the report. Trace how the PHP curl request differs from file_get_contents; done means the curl request is routed through the configured SOCKS proxy under proxychains.