[Python-Dev] PyMem_MALLOC vs PyMem_Malloc

[M.-A. Lemburg]

M.-A. Lemburg wrote:
> Hirokazu Yamamoto wrote:
>> Hello. I found several codes using PyMem_Free to free
>> allocated memory with PyMem_MALLOC (ie: PyUnicode_AsWideCharString)
>>
>> Is it safe?
> 
> Within the interpreter: yes.
>
> In extensions: depends on the platform, but probably not.
> 
> The macros provide faster access to the C lib malloc calls.
> 
> The functions need to be used in extensions in case the interpreter will
> free the resource or the extension wants to free an interpreter
> allocated resource. They provide access to the malloc calls
> used by the interpreter, which may operate on a different heap
> than the extensions.
> 
> Within an extension the macros use the extension heap.
> 
> A subtle, but important difference.

BTW: If you were referring to extensions using PyMem_Free()
to deallocate memory allocated in the interpreter using
PyMem_MALLOC(), then that's exactly how things should be
done.

I was referring to use of the two mentioned APIs within
an extension.

-- 
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source  (#1, Oct 30 2010)
>>> Python/Zope Consulting and Support ...        http://www.egenix.com/
>>> mxODBC.Zope.Database.Adapter ...             http://zope.egenix.com/
>>> mxODBC, mxDateTime, mxTextTools ...        http://python.egenix.com/
________________________________________________________________________

::: Try our new mxODBC.Connect Python Database Interface for free ! ::::


   eGenix.com Software, Skills and Services GmbH  Pastor-Loeh-Str.48
    D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
           Registered at Amtsgericht Duesseldorf: HRB 46611
               http://www.egenix.com/company/contact/