putting php function in template works but putting concatenated function in functions.php doesn't?

Here are two functions I'm working with (line 1 and line 33): http://pastebin.com/GWCJGS1i

If you notice around line 123, I have included the concatenated function . fb_comment_count() .. For some reason, this produces an i开发者_开发问答ncorrect comment count. It just shows zero no matter how many comments there are.

However, if I insert <?php echo fb_comment_count(); ?> into a page template, it works fine. Why does this happen? How can I get the correct comment count to show up with the concatenated function?

Here is the page template:

            <?php get_header();?>

            <section id="content">

                <?php if (have_posts()) : while (have_posts()) : the_post(); ?>

                <article class="post" id="post-<?php the_ID(); ?>">
                    <h2><?php the_title(); ?></h2>
                        <section class="entry">
                            <?php echo fb_comment_count(); ?>
                            <p class="attachment"><?php echo wp_get_attachment_image( $post->ID, 'medium' ); ?></p>
                            <div class="caption">
                                <?php if ( !empty($post->post_excerpt) ) the_excerpt(); // this is the "caption" ?>
                            </div>
                        </section>
                </article>

            <?php comments_template(); ?>

            <?php endwhile; else: ?>

                <p>Sorry, no attachments matched your criteria.</p>

            <?php endif; ?>

            </section>

            <?php get_sidebar(); ?>
            <?php get_footer(); ?>

Two possible causes:

1. The global $post variable is not set when you call your function from functions.php but it is when inside the template.
2. The call to get_posts() is trashing the $post global.