[Insight-developers] memcpy usage in itk and vtk

[Williams, Norman K]

The big issue I ran into with memcpy was where it happened in a case where
it was copying an array of objects whose type was a template parameter,
that could potentially be a C++ class type.

In that case it is potentially disastrous, and probably hard to debug.
std::copy & std::fill have requirements with respect to the type of
objects copied: they need to have an operator= (defined or default) or a
constructor taking the fill type respectively.

In our templated code, throwing a compiler error by enforcing those
constraints is a good thing; where memcpy could silently fail,
std::copy/std::fill will complain.

--
Kent Williams norman-k-williams at uiowa.edu






On 4/10/13 9:04 AM, "Bradley Lowekamp" <blowekamp at mail.nih.gov> wrote:

>Bill,
>
>I think that copy is required for generic programming like much of ITK.
>
>But when you have a known type, I don't see any reason to look down on
>memcpy.
>
>Brad
>
>On Apr 9, 2013, at 5:02 PM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
>
>> Kent says:
>> "There are (before this patch) 88 calls to memcpy
>> in the ITK source code."
>>
>> In VTK, there are 2076 uses of memcpy in 452 classes.. Perhaps the
>>older sibling can learn from the younger.
>>
>> There are 34 uses of std::copy in vtk.
>>
>> Bill
>>
>> --
>> Unpaid intern in BillsBasement at noware dot com
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