c++ - 我如何重载“新”运算符以从辅助内存设备分配内存？

Question

我正在寻找一种从辅助内存设备而不是默认堆分配内存的语法。

我该如何实施？默认情况下，使用malloc()会从堆中获取它......当然必须有另一种方式！

Answer 1

#include <new>

void* operator new(std::size_t size) throw(std::bad_alloc) {
  while (true) {
    void* result = allocate_from_some_other_source(size);
    if (result) return result;

    std::new_handler nh = std::set_new_handler(0);
    std::set_new_handler(nh);  // put it back
    // this is clumsy, I know, but there's no portable way to query the current
    // new handler without replacing it
    // you don't have to use new handlers if you don't want to

    if (!nh) throw std::bad_alloc();
    nh();
  }
}
void operator delete(void* ptr) throw() {
  if (ptr) {  // if your deallocation function must not receive null pointers
    // then you must check first
    // checking first regardless always works correctly, if you're unsure
    deallocate_from_some_other_source(ptr);
  }
}
void* operator new[](std::size_t size) throw(std::bad_alloc) {
  return operator new(size);  // defer to non-array version
}
void operator delete[](void* ptr) throw() {
  operator delete(ptr);  // defer to non-array version
}

Answer 2

您必须构建或调整自己的堆管理器，并重载newand delete，以及new[]and delete[]。使用特殊内存初始化堆管理器。