GlobalMem vs HeapAlloc

[Steven Pringels 3]

Dear,

Could one enlighten me on the pro's and con's over using either memory management technique. Especially the fact that they are now built in
into the new compilers makes using the GlobalMem functions more attractive
than the win32 api Heap functions.

I have been using Heap functions since I encountered the Linked list functions from Don Dickinson and later Paul Squires but I guess replacing them with the GlobalMem wouldn't harm ?

Cheers

Steven

[Michael Mattias]

The GLOBAL MEM functions are PB-proprietary, so we can't compare them against fully-documented methods such as HeapAlloc or GlobalAlloc.

I 'suspect' the GLOBAL MEM functions are currently implemented by the compiler using the GLobalAlloc family of functions. But you never really know.

MCM

[Steven Pringels 3]

So then, I have to address this question to the engineers of PB to give
a pro and con's perspective of the GlobalMem functions vs Heap functions

The audience is listening

[Kev Peel]

If you mean GlobalAlloc vs. HeapAlloc, then underneath they both seem very similar, perhaps only MSDN will document the differences.

One thing is that handle-based memory (GlobalAlloc with GHND flag) is more efficient as Windows will move around the handle-based memory blocks, whereas GPTR will allocated a fixed block and you process' memory will eventually become fragmented, possibly causing "out of memory" or swap file usage. The best method is to allocate memory using handles and lock it (GlobalLock) where needed.

[Michael Mattias]

FWIW:

The GlobalAlloc function allocates the specified number of bytes from the heap. Windows memory management does not provide a separate local heap and global heap.

Note The global functions are slower than other memory management functions and do not provide as many features. Therefore, new applications should use the heap functions. However, the global functions are still used with DDE, the clipboard functions, and OLE data objects.

I think there is also some doc re the Global functions being optimized for blocks of 4 Mb or less but I can't find that anywhere this AM.

Depending on the application (conveniently not described), it's probably moot from a techical perspective and your choice of methods should be based more on maintainability than anything else.