Large memory allocations

[BCS]

Reply to bearophile,

> While allocating lot of memory for a little memory-hungry program, I
> have found results that I don't understand. So I have written the
> following test programs. Maybe someone can give me some information on
> the matter.
> 
> I am using a default install of a 32 bit Win XP with 2 GB RAM (so for
> example I can't allocate 3 GB of RAM). (I presume answers to my
> questions are Windows-related).
> 
> From C (MinGW 4.2.1) this is about the largest memory block I can
> allocate (even it swaps and requires 7+ seconds to run), 1_920_000_000
> bytes:
> 


IIRC without special work, 32bit windows apps can't use more than 2GB of 
total address space regardless of how much ram you have. It's an OS imposed 
limit. With special setup that can be switched to 3GB but that is it.