Adding status message to mail currently I'm using two hooks in my hook.module. hook_form_alter() and hook_mail_alter().

In hook_form_alter() I use drupal_get_messages() to retrieve the status message. 

And I want to use hook_mail_alter() to add this message to the email. But I can't pass the message content from one hook to the other. 

A global variable is not working. Is there a better way? Another hook I'm not aware of?
I suppose you have tried to use drupal_get_messages() within hook_mail_alter() as well?

The reason it probably did not return a value is because the default behavior or drupal_get_messages() is to clear the message queue (so it empty the second time). You can however make it persistent by passing FALSE as a second parameter (see the documentation).

So in your hook_form_alter() use drupal_get_messages(NULL, FALSE) and then you should be able to use it again in hook_mail_alter().