gcc/libstdc++-v3/docs/html/23_containers/wrappers_h.txt

/*****************************************************************
 * Functions to help treat arrays in a uniform manner.  These were
 * inspired by a thread on comp.lang.c++.moderated, started by Dietmar
 * Kuehl and contributed to by the rest of the entire planet.
 *
 * beginof (x), endof (x), lengthof (x) now accompany sizeof, where x
 * can be either a container (currently only sequences) or a builtin
 * array (/not/ a pointer).  The beginof/endof are intended for use in
 * the algorithms library, and lengthof is a "sizing" function.
 *
 * Note example:
 *       char  an_array [17];
 *       cerr << lengthof(an_array) << endl;
 * produces assembly code of
 *       mov 17,register0
 *       call ofstream_put
 * i.e., the template function inlining really does work; g++
 * requires -O3 (or -finline-functions) before it does this, though.
 *
 * pedwards 13Nov98
*/
// beginof
template <class T>
  inline typename vector<T>::iterator beginof (vector<T> &v)
  { return v.begin(); }

template <class T, unsigned int sz>
  inline T* beginof (T (&array)[sz]) { return array; }


// endof
template <class T>
  inline typename vector<T>::iterator endof (vector<T> &v)
  { return v.end(); }

template <class T, unsigned int sz>
  inline T* endof (T (&array)[sz]) { return array + sz; }


// lengthof
template <class T>
  inline typename vector<T>::size_type lengthof (vector<T> &v)
  { return v.size(); }

template <class T, unsigned int sz>
  inline unsigned int lengthof (T (&)[sz]) { return sz; }