$cFormatter = new NumberFormatter('en_US', NumberFormatter::CURRENCY);
  $cFormatter->formatCurrency(123, 'USD');
  $cFormatter->formatCurrency(123, 'BRL');
  $cFormatter->formatCurrency(123, 'GBP');

$cFormatter->formatCurrency(-456, 'USD');

$cFormatter->setTextAttribute(NumberFormatter::NEGATIVE_PREFIX, "-");
$cFormatter->setTextAttribute(NumberFormatter::NEGATIVE_SUFFIX, "");

$cFormatter->setTextAttribute(NumberFormatter::NEGATIVE_PREFIX, "-¤");

$cFormatter = new NumberFormatter('en_US', NumberFormatter::CURRENCY);
$sPattern = $cFormatter->getPattern(); // returns "¤#,##0.00;(¤#,##0.00)";

$sMyPattern = "¤#,##0.00;-¤#,##0.00";
$cFormatter->setPattern($sMyPattern);
$cFormatter->formatCurrency(-456, 'USD');  // returns -$456.00

$locale = 'en_US';
$nf = new NumberFormatter($locale, NumberFormatter::CURRENCY);
$nf->setAttribute(NumberFormatter::MAX_FRACTION_DIGITS, $decimals);

$pattern = str_replace(array('(',')'),'',$nf->getPattern());
$nf->setPattern($pattern);

echo $nf->format($number);