Source-Changes-D archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: CVS commit: src/lib/libutil



On Mon, 31 Dec 2012, Joerg Sonnenberger wrote:
Log Message:
If malloc, calloc, or realloc returns NULL when a size of 0 was
requested, which is allowed by pertinent standards, honor it instead
of bombing.

Do not do this for calloc(x, y) where x != 0 && y != 0 but x*y == 0;
in that case bomb.

The commit message is misleading. We expect calloc(x,y) to return NULL
if x!=0 && y!=0 && x*y==0.

(x!=0 && y!=0 && x*y==0) can be true only if calculating x*y results
in what would loosely be called integer overflow; since the types are
unsigned, it's a well-defined kind of wraparound, not the undefined kind
of overflow.  I'd expect an error like EINVAL rather than an error like
ENOMEM for this case.

--apb (Alan Barrett)


Home | Main Index | Thread Index | Old Index