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Re: Memory allocator

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On 23 Sep 2021 19:15, Scott Lurndal wrote:
> "Alf P. Steinbach" <alf.p.steinbach@gmail.com> writes:
>> On 23 Sep 2021 16:46, Ayush Anshul wrote:
>>> Consider me a C++ noob and go easy on me :|
>>>
>>> Suppose I have a package code and a product code on top of it.
>>> I have control only over the package code side of things. My
>>> memory is allocated/monitored via product code. Can
>>> I override new/malloc on my side to get all allocations done via
>>> that product code function or something similar
>>>
>>> One way I know is that they override global new/malloc on their end.
>>> Other way is I write custom allocator, and use it everywhere(where I
>>> have there allocator function registered as a callback).
>>>
>>> Is there some other easier way?
>>>
>>
>> At the C++ level you can define `operator new` and `operator delete`
>> (plus array variants) in each class.
>>
>> For a Windows DLL you can override `malloc` internally in the DLL, but a
>> Unix shared library is more like a static library, not separate from the
>> client code, so you can't do that with a shared library.
> 
> By why criteria do you consider a unix shared object to be anything like
> a static library?
> 
> "malloc" is a "weak" symbol in all modern unix systems, which means that
> the symbol can be overridden by the application if desired.

The OP is interested in overriding it locally in his library (to be 
precise the OP calls it a "package", I presume that's a library).

A Windows DLL supports that local override where the library uses one 
variant of `malloc` while the client code, the app, uses another.

I believe, but please correct me if I'm wrong, that you can't do that 
with a Unix shared library?

- Alf

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Thread

Memory allocator Ayush Anshul <ayushanshul07@gmail.com> - 2021-09-23 07:46 -0700
  Re: Memory allocator "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-23 18:07 +0200
    Re: Memory allocator scott@slp53.sl.home (Scott Lurndal) - 2021-09-23 17:15 +0000
      Re: Memory allocator "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-23 21:59 +0200
        Re: Memory allocator scott@slp53.sl.home (Scott Lurndal) - 2021-09-24 14:58 +0000
          Re: Memory allocator "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-24 18:55 +0200
            Re: Memory allocator scott@slp53.sl.home (Scott Lurndal) - 2021-09-24 17:23 +0000

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