This section describes how you can use DosAllocSharedMem, DosGiveSharedMem, DosGetSharedMem, and DosGetNamedSharedMem to use shared memory.

There are three types of shared memory:

• Named, where a process allocates and names shared memory. A second process can use the shared memory by using DosGetNamedSharedMem, specifying the name of the shared memory.

• Unnamed giveable, where a process gives another process access to shared memory with DosGiveSharedMem, using the PID of the second process.

• Unnamed gettable, where a process knows the address of shared memory they want to use (allocated by another process), gets permission to use that memory with DosGetSharedMem, and then uses the shared memory.

The difference among these different types of shared memory is not in how the memory is allocated by the original process, but in how the second process gets permission to use and access to the shared memory. All three types of shared memory are allocated with the same call: DosAllocSharedMem, using various parameters.