4 Features

Features provided by the festplugin system are very minmal to allow the maximum of flexibility. In a certain sens it only exports the suitable dlopen methods of the c library to the scheme interface. Anyway there should be a way to keep track of the handle to allow plugin to be closed. The rest of the tasks is dedicated to the plugin developers. Therefore only an open (4.1) and a close (4.2) method are provided. The first one can surely not be called from the plugin itself as anyone can understand. For the second one it might look more subtle but if a plugin try to close itself it will lead to a segfault. Hence it seems to be clear at this point that when the plugin should be closed from the scheme level, the scheme level should provide the “handle” of the given plugin. In the actual implementation, this handle can be kept in a class that provides a suitable handle() method. An object of this class type will be returned by the open method and passed as an argument to the close method. Such an object should in fact inherit from the FP_MANAGER class defined in festplugin.H.

More precisely :