malloc does not return null when out of memory

[Malcolm Kay]

On Thu, 24 Jul 2003 23:11, Gabor wrote:
> On Wed, Jul 23, 2003 at 02:09:00PM -0700, Doug White wrote:
> # On Wed, 23 Jul 2003, Gabor wrote:
> #
> # > We have a little soekris box running freebsd that uses racoon for key
> # > management.  It's used for setting up an ipsec tunnel.  I noticed that
> # > one of these devices lost the tunnel this morning.  I looked in the
> # > log and saw this
> # >
> # > Jul 23 01:37:57 m0n0wall /kernel: pid 80 (racoon), uid 0, was killed:
> out of swap space #
> # [...]
> #
> # > Here is the tail end of the output.  It dies when trying to poke at
> # > the memory using memset.  If I just malloc without the memset, it
> # > never even dies.
> #
> # That's normal. If you malloc() memory and never touch it then it is never
> # actually allocated.
>
> It's not normal.  If malloc cannot allocate memory it should return a
> null pointer.  How would my application know there is no more memory?
> Dying is not a very good behavior.  The C standard and even the man
> page says that malloc will return null when there is no more memory to
> be had by the process.

While this might be a desirable state of affairs I can't find any statement 
in the (draft) standard or the man page that malloc returns null when there is 
no more memory (whatever that might mean) . The (draft) standard says it 
either returns a pointer to allocated memory or null, without any reason 
given for the different behaviours. The man page merely says null if the 
call fails without reference to why.

Malcolm Kay