Websiteguy on "Obstart Shortcode"

Hi

I am trying to make a shortcode that I can add insert this: <?php echo sharing_display(); ?>.

I tried an obstart function.

function ShareShortcode() {
ob_start('<?php echo sharing_display(); ?');
}
add_shortcode('jpshare', 'ShareShortcode');

I may be on the complete wrong track.

Can you please give me the code.

Thanks