Checks if action_name is valid.
action_name is valid if it consists only of alphanumeric characters,
plus '-' and '.'. The empty string is not a valid action name.
It is an error to call this function with a non-utf8 action_name.
action_name must not be NULL.
Since 2.38
Checks if action_name is valid. action_name is valid if it consists only of alphanumeric characters, plus '-' and '.'. The empty string is not a valid action name. It is an error to call this function with a non-utf8 action_name. action_name must not be NULL. Since 2.38