Re: Windows array allocation problem

Roy Lewallen wrote:
(snip)

It appears that some people have taken "available virtual memory" to mean the entire 2GB which is allotted to the application, and have explained that the entire amount can't be used. I understand that, but that's not what I meant. By "available virtual memory" I meant the amount that's actually available for use at the moment that the array allocation is made. This would mean the original 2GB less whatever has already been used by the program, stack, other allocations, and so forth.

Another that I haven't seen mentioned yet is fragmentation.

If you, or the library routines your program calls (such as I/O
routines) allocates some memory blocks and then deallocates some but
not all of them it might be that the available virtual memory is
not contiguous. ALLOCATE will (as far as I know) always allocate a
contiguous block of memory. Functions that report the total amount
available will sum up the available blocks.

My program has provision for approximately predicting the additional memory which will be used later in the program, and adjusts the allocation accordingly. But it needs to know how much it has altogether to work with. GlobalMemoryStatus(Ex) reports a "total virtual memory" (2GB) and "available virtual memory" (less than 2GB). I had assumed that the "available virtual memory" was the amount currently available for such purposes as array allocation.

-- glen

.

Relevant Pages

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