Virtuozzo Virtualization SDK C API Reference
Define type of user's callback function
PRL_DISK_CALLBACK is a function prototype for implementing callback functions for use in PHT_VIRTUAL_DISK calls.
A pointer to a callback function can be passed to another function that accepts it as a parameter. The operation initiated by that function will be performed in the background thread, which will call the callback function (possibly more than once) passing to it intermediate results or the final result of the operation.