On Mon, Apr 2, 2012 at 14:40, Joakim Tjernlund wrote:
Marek Vasut marek.vasut@gmail.com wrote on 2012/04/02 20:00:03:
Dear Joakim Tjernlund,
Depends, if writing generic code for lots of OS:es you cannot rely malloc(0). Writing kernel code you can.
No you cannot. It's in the spec you cannot and you have to behave according to the spec, not according to kernel.
How so? The kernel is its own system and has it own rules and it is wise to follow them.
correct
From Scotts example we already know there is kernel code that relies on malloc(0) not returning NULL.
Sure, but that means the code is messed up.
ohh, I don't think the kernel people will agree: http://lwn.net/Articles/236920/ But feel free to bring it up.
i dislike the malloc(0) returning valid memory, but i'm fine with the ZERO_SIZE_PTR idea. i think we'd have to delegate this to arches though to pick a pointer that'd work for them ... certainly the kernel definition won't work for us: #define ZERO_SIZE_PTR ((void *)16)
address 0 and higher is valid memory on many platforms. for Blackfin systems, (-16) should work. -mike