[M3devel] unsafety in RTAllocator (Malloc/Free)

[Jay]

> What do you need them for? RTAllocator is there so one can allocate

How do I get a typecode in C?
 
Perhaps the attached is unnecessarily elaborate?
Or the new/dispose functions should be moved to Modula-3?
 Or eliminated and the small number of callers can say NEW(ARRAY OF CHAR, Uucontext.Size)?
 
 
 - Jay


----------------------------------------
> From: hosking at cs.purdue.edu
> To: jay.krell at cornell.edu
> Date: Tue, 3 Feb 2009 19:35:38 +1100
> CC: jkrell at elego.de; m3devel at elegosoft.com
> Subject: Re: [M3devel] unsafety in RTAllocator (Malloc/Free)
>
> On 3 Feb 2009, at 19:07, Jay wrote:
>
>>
>> Sorry, fair enough. I don't think about safety much.
>>
>>
>> Can I put these in a new unsafe RTAllocateUnsafe.i3 or
>> RTUnsafeAllocator.i3?
>> And then the function names I had come up with MallocUninitialized,
>> MallocZeroed.
>
> What do you need them for? RTAllocator is there so one can allocate
> by typecode. I don't see the point of Malloc/Free.
>
>> Using array of char seems non-ideal to me somehow.
>> It seems like a "workaround".
>> It doesn't seem really any safer than not having a type at all.
>> I understand, the array, the type, does imply a size, and so I would
>> get some bounds checking against it, except I never access these
>> things anyway, I just pass them on to unsafe C code.
>>
>>
>> Related but tangential question, something I also didn't pay close
>> enough attention to:
>> What is the deal with OutOfMemory vs. RuntimeError.T.OutOfMemory?
>
> The first is an explicit exception while the latter is implicit.
>
>> Why don't Malloc, GetUntracedOpenArray, GetUntracedObj, etc. raise
>> OutOfMemory directly?
>
> Because the exception is implicit. Any procedure can raise a
> RuntimeError.
>
>>
>>
>>
>> - Jay
>>
>>
>> ----------------------------------------
>>> To: jkrell at elego.de
>>> Date: Mon, 2 Feb 2009 22:21:53 -0800
>>> From: mika at async.caltech.edu
>>> CC: m3devel at elegosoft.com
>>> Subject: Re: [M3devel] [M3commit] CVS Update: cm3
>>>
>>> Jay Krell writes:
>>>> CVSROOT: /usr/cvs
>>>> Changes by: jkrell at birch. 09/02/03 06:17:25
>>>>
>>>> Modified files:
>>>> cm3/m3-libs/m3core/src/runtime/common/: RTAllocator.i3
>>>> RTAllocator.m3
>>>>
>>>> Log message:
>>>> expose RTAllocator.MallocZeroed (calloc), and RTAllocator.Free
>>>
>>> RTAllocator isn't UNSAFE is it (it isn't in my installation)? Surely
>>> you can't have Free in a non-UNSAFE interface...
>>>
>>> Mika
>>>
>>>> introduce internal RTAlloc.MallocUninitialized
>>>>
>>>> These include Disable/EnableSwitching, and
>>>> raising exceptions upon failure.
>>>> (Disable/Enable only do something for user threads).
>
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