lundi 2 janvier 2017

Bare metal without global operator new

Consider safety software, where dynamic allocation in general is disallowed and exceptions are disallowed. Dynamic allocation is allowed only when class explicity defines operator new and delete. Using operator new for others class should cause compilation failure.

The simplest way to cause compilation failure in described situation is to remove global new operator:

void* operator new(std::size_t) = delete;

On the one hand this cause side effects with standard library. For example including <array> propagates inclusion to <new_allocator> by <stdexcept>. <new_allocator> uses ::new operator and this cause build fail even when You don't want to use exception and memory allocation. According to Scoot Meyers <array> should be bare metal friendly.

On the other hand this cause error with compiler built-in operator

src/main.cpp:91:31: error: deleted definition of 'void* operator new(std::size_t)'
 void* operator new(std::size_t) = delete;                               ^
<built-in>: note: previous declaration of 'void* operator new(std::size_t)'

Is there any solution to ban ::new and use <array>?

Is there any solution to ban ::new globally at all?

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