Floating point rounding modes: we should restrict them slightly

[Don]

Walter Bright wrote:
> Brad Roberts wrote:
>> Walter Bright wrote:
>>> strlen() is safe, while strcpy() and printf() are not.
>>
>> You sure?  Does running beyond the bounds of the array if there's no null
>> termination count as safe some how? :)
> 
> Yes. Memory safety is defined as being free of memory corruption errors. 
> Simply reading memory out of bounds does not corrupt memory.

It does result in undefined behaviour, though. I don't see much 
difference. (Corrupting memory is a problem only because you read it 
again afterwards...)

> Note that it is ok for a memory safe program to generate a seg fault.

It'd be OK if it was guaranteed to generate a seg fault. But I don't 
think that's true here.

> 
> printf() is not memory safe because of the %n format.