add/update/get_options

Use the same function. Multsite still uses one db by default, and each blog’s options table is prefixed with a blog ID number. wp_16_options, for example.

THe only multisite specific options would be global.

Ok but if I use get_option(‘name’) in a plugin, will it be the same option in each site ? or can i change the value of the option for one site without changing in in another site ?

Ok but if I use get_option(‘name’) in a plugin, will it be the same option in each site ?

No, it won’t. You’re getting the $blogid right before that, correct?

You could also use get_site_option() or update_site_option() if you need to set site-wide options.

No, i do nothing else right now… Could you give me an example ?

If you’re just writing a regular plugin for single WordPress, just write it according to the guidelines. It should still work in multisite if it is activated on a per site basis.

@cedric – Here is a quick bit of code I use to hit every site and see what theme they are using:

$blogs = $wpdb->get_results("SELECT blog_id, domain, path FROM wp_blogs");
  $i = 0;
  foreach($blogs as $blog)
  {
    $blogtemplate= get_blog_option($blog->blog_id, 'template');
    if($blogtemplate==$old_template)
    {
      echo "<p>BLOG <a href='https://" . $blog->domain . $blog->path ."'>https://".$blog->domain . $blog->path."</a> changing from <strong>$blogtemplate</strong> to <strong>$new_template</strong><br>";
      switch_to_blog($blog->blog_id);
      switch_theme($new_template, $new_template);
      echo "</p>";
      $i++;
    }
  }

Does this help?