Question

I want to wrap my code in a function (and then put it in functions.php) so that I can call it elsewhere but my code fails as soon as I wrap it in a function.

I think this may be a scope issue, do I have to pass the the post number somehow to the function? If I get rid of the function that’s wrapped around the query, the code works fine.

I’m guessing that the code is irrelevant really (although I may be wrong) – it’s more to do with the fact that it’s a loop and a function.

        <?php function getGallery2() { ?>
            <!-- 1. search for any pages with a custom field of 'test' that have a value of 'yes' -->
            <?php query_posts('meta_key=Gallery - Promotion Gallery Photo Link&post_type=page'); ?>

            <?php while ( have_posts() ) : the_post(); ?>
                <!-- 2. echo the test field -->
                <?php $link =  get_post_meta($post->ID, 'Gallery - Promotion Gallery Photo Link', true); ?>
                <?php $alt =  get_post_meta($post->ID, 'Gallery - Promotion Gallery Photo Alt text', true); ?>
                <img src="<?php echo $link ?>" alt="<?php echo $alt ?>" />
            <?php endwhile;?>

            <?php wp_reset_query(); ?>

        <?php } ?>

        <?php getGallery2(); ?>

Answer 1

$post is not in the functions scope.

You can add global $post; to the top of the function or you can include it as a parameter like this:

function getGallery2($post){
    // code
}

echo getGallery2($post)

Code inside a function can only see variables that were created within the same function or in global scope. Meaning the $post object is undefined.

//
On a slightly off topic note, you have lots of HTML comments within PHP. You could easily tidy things p by making it all PHP.

EDIT:

function getGallery2(){

    global $post;

    // 1. search for any pages with a custom field of 'test' that have a value of 'yes' -->
    query_posts('meta_key=Gallery - Promotion Gallery Photo Link&post_type=page'); 

    while ( have_posts() ) : the_post(); 
        // 2. echo the test field -->
        $link =  get_post_meta($post->ID, 'Gallery - Promotion Gallery Photo Link', true); 
        $alt =  get_post_meta($post->ID, 'Gallery - Promotion Gallery Photo Alt text', true); 
        echo '<img src="'.$link.'" alt="echo $alt " />';
    endwhile;

    wp_reset_query(); 

} 

getGallery2();