Документация g++

$ ./return123 
$ echo $?
123

$ grep new /usr/include/c++/4.0.0/new 
/** @file new
 *  The header @c new defines several functions to manage dynamic memory and
   *  @brief  Exception possibly thrown by @c new.
   *  errors from the throwing forms of @c new.  */
  /** If you write your own error handler to be called by @c new, it must
  typedef void (*new_handler)();
  new_handler set_new_handler(new_handler) throw();
 *  - normal single new and delete (no arguments, throw @c bad_alloc on error)
 *  - normal array new and delete (same)
 *  - @c nothrow single new and delete (take a @c nothrow argument, return
 *  - @c nothrow array new and delete (same)
 *  Placement new and delete signatures (take a memory address argument,
void* operator new(std::size_t) throw (std::bad_alloc);
void* operator new[](std::size_t) throw (std::bad_alloc);
void* operator new(std::size_t, const std::nothrow_t&) throw();
void* operator new[](std::size_t, const std::nothrow_t&) throw();
// Default placement versions of operator new.
inline void* operator new(std::size_t, void* __p) throw() { return __p; }
inline void* operator new[](std::size_t, void* __p) throw() { return __p; }