Memory on the iPhone

Now here is the question: How much memory does the iPhone have? How much memory is OK for applications to use? Curious as I am I did some research and wrote a little test project. This got me some odd results.
According to what you find on the net the iPhone has a total memory size of 128 MB and your application shocould not use more than 46 MB of it. but what happens exactly when you try to obtain more?
So I wrote a little application that continuously allocates more and more memory. In fact it mallocs/frees the memory on every timer tick.
Now this is where it gets odd. while the sysctl () CILS do report something around 128 MB of ram I can malloc () way beyond this. in fact callingmalloc (700000000) does not fail at all! When I run the application on just the iPhone it will stop at around 719 MB. when I run it through Instruments the whole devices freezes at around 46 MB. this has been reproduced on 2.1 and 2.2 on different devices. www.2cto.com

-(Void) tick
{
Allocated = allocated + size;

If (allocatedPtr ){
Free (allocatedPtr );
}

AllocatedPtr = malloc (allocated );

If (! AllocatedPtr ){
NSLog (@ "out of memory at % ld", allocated );
...

Later I found someone who stumbled into ss the same thing.
Lazyweb: what is going on here?
You can download the test application here. But as a disclaimer: you run this code on your own risk!

Update:
So afterall this means the result of malloc () has a different semantic of what I expected. Adding the following piece of code makes the program behave and gives the expected result.

Long * p = (long *) allocatedPtr;
Long count = allocated/sizeof (long );
Long I;
For (I = 0; I <count; I ++ ){
* P ++ = 0x12345678;
}

So it turns out if you allocate (and use !) Around 46-50 MB in your iPhone application it will just get terminated.

From volcan1987