More C++ Idioms/Free Function Allocators

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Free Function AllocatorsEdit


Allow containers to use custom allocators without creating a new type

Also Known AsEdit


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

Solution and Sample CodeEdit

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) {

Known UsesEdit

  • boost::ptr_container

Related IdiomsEdit