28.2 Built-In Function Descriptions
This section describes the programmer interface to the compiler built-in
functions. Since the functions are “built in,” there are no header files associated with
them. Similarly, there are no command-line switches associated with the built-in functions
– they are always available. The built-in function names are chosen such that they belong
to the compiler’s namespace (they all have the prefix __builtin_
), so they
will not conflict with function or variable names in the programmer’s namespace.