DosSubSetMem Parameter - flag

flag (ULONG) - input

Indicators describing the characteristics of the memory object that is being suballocated.

This parameter consists of the following bit fields:

Bit

Description
0
DOSSUB_INIT (0x00000001)
This bit must be set to initialize a memory object for suballocation. Otherwise, the request is to attach a process to a shared memory pool that was previously initialized by another process using DosSubSetMem.
1
DOSSUB_GROW (0x00000002)
If this bit is set, then the request is to increase the size of the memory pool being managed. Bit 0 then has no meaning.
2
DOSSUB_SPARSE_OBJ (0x00000004)
Bit 2 is set if the requester wants a suballocation function to manage the commitment of the pages spanned by the memory pool.

All of the pages spanned by the object must be initially uncommitted. If this bit is clear, the suballocation function assumes that all of the pages spanned by the memory pool are valid and committed.

For a DosSubSetMem(Grow) request, the setting of this bit should be the same as when the memory pool was initialized. Otherwise, an error is returned.

3
DOSSUB_SERIALIZE (0x00000008)
This bit is set if the requester requires access to the memory pool to be serialized.

For shared memory pools, the first DosSubSetMem(Init or Serialize) request causes the memory pool to be created and opened for the requesting process.

Subsequent DosSubSetMem(Attach or Serialize) requests cause the shared memory pool to be attached to the requesting process. The requesting process must first gain access to the memory object that the pool resides in. DosSubSetMem(Attach) is indicated when bit 0 is off.

On a DosSubSetMem(Grow) request, bit 3 should be the same as when the memory pool was initialized, or an error is returned.

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