<?php
function conectar_correios5_curl($url){
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_URL, $url);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
	curl_setopt($ch, CURLOPT_FAILONERROR, false);
	$result = curl_exec($ch);
	curl_close($ch);
	$xml = @simplexml_load_string($result);
	if(!is_object($xml)) {
	return false;
	}
	return $xml;
}

//testa a conexao aos correios
$url = 'http://ws.correios.com.br/calculador/CalcPrecoPrazo.aspx?nCdEmpresa=&sDsSenha=&sCepOrigem=22450000&sCepDestino=22450000&nVlPeso=1,00&nCdFormato=1&nVlComprimento=20,00&nVlLargura=20,00&nVlAltura=20,00&sCdMaoPropria=n&nVlValorDeclarado=27,00&sCdAvisoRecebimento=n&nCdServico=41106,40010,40045&nVlDiametro=0&StrRetorno=xml';

print_r(conectar_correios5_curl($url));