$bh_errorMessages=array();
function bh_save_details(){
global $post, $bh_errorMessages;
$bh_errorMessages[]="test error";
$bh_errorMessages[]="another test error";
}
function bh_printErrorMessages(){
global $bh_errorMessages;
$output='';
if(!empty($bh_errorMessages)){
$output='<div class="error">';
foreach($bh_errorMessages as $msg){
$output.='<p>'.$msg.'<p>';
}
$output.='</div>';
}
echo $output;
}
add_action('admin_notices', 'bh_printErrorMessages');
add_action('save_post', 'bh_save_details');