Manual Pages  — DECLARE_GEOM_CLASS

The arguments to DECLARE_GEOM_CLASS() are:

class	The g_class structure which describes a GEOM class.
mod_name	A kernel module name (not a class name!).

Structure g_class contains data describing the class. They are:

const char * name	Class name.
g_taste_t * taste	Pointer to function used for taste event handling. If it is non- NULL it is called in three situations:
	On class activation, all existing providers are offered for tasting.
	When new provider is created it is offered for tasting.
	After last write access to a provider is closed it is offered for retasting (on first write open event "spoil" was sent).

g_config_t * config	This field is not used anymore, its functionality was replaced by the ctlreq field.
g_ctl_req_t * ctlreq	Pointer to function used for handling events from userland applications.
g_init_t * init	Pointer to function which is called right after class registration.
g_fini_t * fini	Pointer to function which is called right before class deregistration.
g_ctl_destroy_geom_t * destroy_geom	Pointer to a function which is called for every geom on class unload. If this field is not set, the class can not be unloaded.

Only a name field is required; the rest are optional.