More C++ Idioms/Free Function Allocators

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Free Function Allocators[edit]

Intent[edit]

Allow containers to use custom allocators without creating a new type

Also Known As[edit]

Motivation[edit]

C++ standard allocators have serious problems, because they change the underlying type of the container.

Solution and Sample Code[edit]

This idiom is superior to the way that std::allocators work the whole idiom is outlined here.

struct user_allocator_nedmalloc
{
	typedef std::size_t size_type;
	typedef std::ptrdiff_t difference_type;
 
	static inline char* malloc(const size_type bytes) {
		return reinterpret_cast<char*>(nedmalloc(bytes));
	}
 
	static inline void free(char* const block) {
		nedfree(block);
	}
};

Known Uses[edit]

  • boost::ptr_container

Related Idioms[edit]

References[edit]