Int 31H Function 0D01H
Free Shared Memory
Deallocates a shared memory block.
AX = 0D01H
SI:DI = handle of shared memory block to free
if function successful
Carry flag = clear
if function unsuccessful
Carry flag = set
AX = error code
- The shared memory handle becomes invalid after the shared memory
block is deallocated, and should not be used in any other function
call (such as serialization).
- The host maintains virtual machine use counts and a global use
count for each shared memory block. A virtual machine use count is
the number of allocation calls (Int 31H Function
0D00H) that have been issued by a particular virtual machine for
the shared block, while the global use count corresponds to the number
of virtual machines which have access to the block. When a virtual
machine use count reaches zero, the clients in that virtual machine no
longer have addressability to the shared memory block; when the global
use count reaches zero, the shared memory block is destroyed by the
- It is the client's responsibility to free any descriptors that it
has allocated to map the shared memory block.
- Applications should not depend on this function to release a
previous successful serialization for the same shared memory block.
Serialization is only released by this function when the virtual
machine use count goes to 0 (i.e., the client no longer has access to
the shared memory block).