an application
writer should include the file '<readline/readline.h>' in any file that
uses Readline's features.  Since some of the definitions in 'readline.h'
use the 'stdio' library, the file '<stdio.h>' should be included before
'readline.h'.

   'readline.h' defines a C preprocessor variable that should be treated
as an integer, 'RL_READLINE_VERSION', which may be used to conditionally
compile application code depending on the installed Readline version.
The value is a hexadecimal encoding of the major and minor version
numbers of the library, of the form 0xMMMM.  MM is the two-digit major
version number; MM is the two-digit minor version number.  For Readline
4.2, for example, the value of 'RL_READLINE_VERSION' would be '0x0402'.

* Menu:

* Readline Typedefs::	C declarations to make code readable.
* Function Writing::	Variables and calling conventions.