stl_construct.h

#ifndef __SGI_STL_INTERNAL_CONSTRUCT_H
#define __SGI_STL_INTERNAL_CONSTRUCT_H

#include <new.h>   // 需要placement new的原型

__STL_BEGIN_NAMESPACE

// construct and destroy.  These functions are not part of the C++ standard,
// and are provided for backward compatibility with the HP STL.  We also
// provide internal names _Construct and _Destroy that can be used within
// the library, so that standard-conforming pieces don't have to rely on
// non-standard extensions.

// Internal names

template <class _T1, class _T2>
inline void _Construct(_T1* __p, const _T2& __value) {
  new ((void*) __p) _T1(__value);
}

template <class _T1>
inline void _Construct(_T1* __p) {
  new ((void*) __p) _T1();
}

template <class _Tp>
inline void _Destroy(_Tp* __pointer) {
  __pointer->~_Tp();
}

template <class _ForwardIterator>
void
__destroy_aux(_ForwardIterator __first, _ForwardIterator __last, __false_type)
{
  for ( ; __first != __last; ++__first)
    destroy(&*__first);
}

template <class _ForwardIterator> 
inline void __destroy_aux(_ForwardIterator, _ForwardIterator, __true_type) {}

template <class _ForwardIterator, class _Tp>
inline void 
__destroy(_ForwardIterator __first, _ForwardIterator __last, _Tp*)
{
  typedef typename __type_traits<_Tp>::has_trivial_destructor
          _Trivial_destructor;
  __destroy_aux(__first, __last, _Trivial_destructor());  //是否为trivial destructor，避免影响效率
}

template <class _ForwardIterator>
inline void _Destroy(_ForwardIterator __first, _ForwardIterator __last) {
  __destroy(__first, __last, __VALUE_TYPE(__first));
}

inline void _Destroy(char*, char*) {}
inline void _Destroy(int*, int*) {}
inline void _Destroy(long*, long*) {}
inline void _Destroy(float*, float*) {}
inline void _Destroy(double*, double*) {}
#ifdef __STL_HAS_WCHAR_T
inline void _Destroy(wchar_t*, wchar_t*) {}
#endif /* __STL_HAS_WCHAR_T */

// --------------------------------------------------
// Old names from the HP STL.

template <class _T1, class _T2>
inline void construct(_T1* __p, const _T2& __value) {
  _Construct(__p, __value);
}

template <class _T1>
inline void construct(_T1* __p) {
  _Construct(__p);
}

template <class _Tp>
inline void destroy(_Tp* __pointer) {
  _Destroy(__pointer);
}

template <class _ForwardIterator>
inline void destroy(_ForwardIterator __first, _ForwardIterator __last) {
  _Destroy(__first, __last);
}

__STL_END_NAMESPACE

#endif /* __SGI_STL_INTERNAL_CONSTRUCT_H */

construct –>_Construct

destroy->_Destroy->__destroy->__destroy_aux