Looks up the #GType to be used when creating socket connections on sockets with the specified family, type and protocol_id.
If no type is registered, the #GSocketConnection base type is returned.
a #GSocketFamily
a #GSocketType
a protocol id
a #GType
Looks up the #GType to be used when creating socket connections on sockets with the specified family, type and protocol_id.
If no type is registered, the #GSocketConnection base type is returned.