关于c++:C内存管理3placement-new

• placement new 容许咱们将 object 构建于 allocated memory 中;
• 没有所谓 placement delete， 因为 placement new 基本没调配 memory;

• 亦或称说与 placement new 对应的 operator delete 为 placement delete。

  #include <new>char *buf = new char[sizeof(Complex) * 3];Complex *pc = new(buf) Complex (1, 2);// ...delete[] buf;

Complex *pc = new(buf) Complex (1, 2);编译器转换为 ==>Complex *pc;try {    void* mem = operator new (sizeof(Complex), buf); // allocate    pc = static_cast<Complex*>(mem);                 // cast    pc->Complex::Complex(1, 2);                      // construct}catch(std::bad_alloc) {    // 若 allocation 失败就不执行 constructor }

void* mem = operator new (sizeof(Complex), buf);源码实现 ==>void *operator new (size_t, viud *loc){    return loc;}