wordpress plugin: query post-ID in plugin?

Question

hey guys, maybe some of you have experience with programming wordpress plugins. I have a probably rather simpel question, but i couldn\'t find anything on the web.

Answer 1

Filters should return, not echo.

function test($content) {
    global $post;
    return 'id: ' . $post->ID . '
' . $content;
}

In order to look at the post object properties you must bring $post into the scope of the function, that's what this line does..

global $post;

Which then allows the reference to the object's ID, eg.

$post->ID;

See here for help understanding actions and filters.
http://codex.wordpress.org/Plugin_API

Example filter.
http://codex.wordpress.org/Plugin_API#Example