get_category_link in single

I resolved it by creating a new function based on the_category which works perfectly in a single.

This is the only way I could extract the category link in a single

Sure, zeroo,

function get_categoria_post($separator = '', $parents='') {
	global $wp_rewrite;
	$categories = get_the_category();
	if (empty($categories))
		return apply_filters('the_category', __('Uncategorized'), $separator, $parents);

	$rel = ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) ? 'rel="category tag"' : 'rel="category"';

	$thelist = '';
	if ( '' == $separator ) {
		$thelist .= '';
		foreach ( $categories as $category ) {
			$thelist .= "";
			switch ( strtolower($parents) ) {
				case 'multiple':
					if ($category->parent)
						$thelist .= get_category_parents($category->parent, TRUE);
					$thelist .=  get_category_link($category->term_id);
					break;
				case 'single':
					$thelist .= get_category_link($category->term_id);
					if ($category->parent)
						$thelist .= get_category_parents($category->parent, FALSE);
					$thelist .= $category->name.'</a></li>';
					break;
				case '':
				default:
					$thelist .= get_category_link($category->term_id);
			}
		}
		$thelist .= '';
	} else {
		$i = 0;
		foreach ( $categories as $category ) {
			if ( 0 < $i )
				$thelist .= $separator . ' ';
			switch ( strtolower($parents) ) {
				case 'multiple':
					if ( $category->parent )
						$thelist .= get_category_parents($category->parent, TRUE);
					$thelist .= get_category_link($category->term_id);
					break;
				case 'single':
					$thelist .= get_category_link($category->term_id);
					if ( $category->parent )
						$thelist .= get_category_parents($category->parent, FALSE);
					$thelist .= "$category->cat_name</a>";
					break;
				case '':
				default:
					$thelist .=get_category_link($category->term_id);
			}
			++$i;
		}
	}
	return apply_filters('the_category', $thelist, $separator, $parents);
}

Check it out in justtellmewhy.com