Tools.h++ Manual

104011 Tandem Computers Incorporated 21-195

Public pure virtual functions

virtual RWHandle allocate() = 0

Allocates a page off the abstract heap and returns a handle for it. If the

specializing class is unable to honor the request, then it should return a zero

handle.

virtual void deallocate(RWHandle h) = 0;

Dallocate the page associated with handle

. It is not an error to deallocate a

zero handle.

virtual void dirty(RWHandle h) = 0;

Declare the page associated with handle

to be "dirty". That is, it has changed

since it was last locked. The page must be locked before calling this function.

virtual void* lock(RWHandle h) = 0;

Lock the page, swapping it into physical memory, and return an address for it.

A nil pointer will be returned if the specializing class is unable to honor the

lock. The returned pointer should be regarded as pointing to a buffer of the

page size.

virtual void unlock(RWHandle h) = 0;

Unlock a page. A page must be locked before calling this function. After

calling this function the address returned by

lock()

is no longer valid.