This part deals with the functions called and objects created automatically during the course of a program's existence.

While we can't reproduce the contents of the Standard here (you need to get your own copy from your nation's member body; see our homepage for help), we can mention a couple of changes in what kind of support a C++ program gets from the Standard Library.

C++ has the following builtin types:

Specializing parts of the library on these types is prohibited: instead, use a POD.

The header `limits`

defines
traits classes to give access to various implementation
defined-aspects of the fundamental types. The traits classes --
fourteen in total -- are all specializations of the template class
`numeric_limits`

, documented here
and defined as follows:

template<typename T> struct class { static const bool is_specialized; static T max() throw(); static T min() throw(); static const int digits; static const int digits10; static const bool is_signed; static const bool is_integer; static const bool is_exact; static const int radix; static T epsilon() throw(); static T round_error() throw(); static const int min_exponent; static const int min_exponent10; static const int max_exponent; static const int max_exponent10; static const bool has_infinity; static const bool has_quiet_NaN; static const bool has_signaling_NaN; static const float_denorm_style has_denorm; static const bool has_denorm_loss; static T infinity() throw(); static T quiet_NaN() throw(); static T denorm_min() throw(); static const bool is_iec559; static const bool is_bounded; static const bool is_modulo; static const bool traps; static const bool tinyness_before; static const float_round_style round_style; };

For **g++**, `NULL`

is
`#define`

'd to be
`__null`

, a magic keyword extension of
**g++**.

In his book *Effective
C++*, Scott Meyers points out that the best way
to solve this problem is to not overload on pointer-vs-integer
types to begin with. He also offers a way to make your own magic
`NULL`

that will match pointers before it
matches integers.