Slackware :: Php Curl Can't Resolve Host Getting Error?

I have a strange problem with using curl function in php on slackware machines. So far I tested this on 2 PCs. I din't test it on any other distributions, so I don't know if it's only slackware problem.

Problem is that I can't use php curl in normal way. It can be tested wit simple code:

Code:
$ch = curl_init("url");
$content = curl_exec($ch);
if (curl_error($ch)) {
echo(curl_error($ch) . "<br>");
}
echo($content);
When I'm opening this php script in browser I'm getting error message:

Code:
Couldn't resolve host 'google.lv'
but I can use curl command in terminal, also it works when I run this php script in terminal like:

Code:
php ./curl_test.php
So problem is not in curl or php itself, but in apache, because this happens only when this script is running in apache.

Searching google a lot, I got to conclusion that apache can't read /etc/resolve.conf file during startup. Strange thing is that it happens only when httpd starts during system startup, but if I'm stopping httpd and starting it again manually, it works as it should until I'll reboot my PC. Restarting httpd also do not work, I need to do start -> stop.

I think that apache reads /etc/resolve.conf only when it starting up and as I have DHCP, maybe network is still not ready at the moment of httpd startup.

I didn't try to configure php as php-cgi instead of apache module, I think then it would work normally because each php script would be separate process and it would read dns information each time, so the same like starting php script in terminal with command:

Code:
php ./curl_test.php
I think there are some ways to workaround it, e.g. delay somehow start of httpd during system startup, or something like that, but I want to find reason of this problem and make it work without any workaround.