Daniel Veillard wrote:
On Wed, Mar 21, 2007 at 01:55:35PM +0000, Mark McLoughlin wrote:- I think the use case is a little different - generally in libvirt, we're only allocating very small chunks where the CPU hit for initialisation would be negligible and would never show up on aprofile. I'd prefer to take the minor hit of zero-initialising most/all memory for programming ease.- If our wrappers always zero-initialise, we don't need the "initialise to -1 when debugging" thing.- If we rely on calloc() zero-initialising in our wrappers, we give opportunity for libc to optimise where it knows the memory is already initialised - e.g. where it's mmap()ing the memory from /dev/zerookay, okay, let's use calloc() for libvirt, but then there is a number of places where I probably used memset() for zeroing, they should all be cleaned up.
<pedant>Note that neither calloc nor memset really work on unusual architectures where null pointers aren't represented by all-bits-zero. So code like:
struct { void *ptr; } *s;
s = malloc (sizeof (*s));
memset (s, 0, sizeof (*s));
/* ... */
if (s->ptr == NULL) { do something }
isn't portable. There's some really strange stuff here about this:
http://www.ex-parrot.com/~chris/random/initialise.html
</pedant>
Rich.
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