.. syntax:: #
  #<directive>[ <arguments...>]
  :name: preprocessor
  :title: Preprocessor directives

  .. directive: include | define | if | ifdef | ifndef | else | elif | endif | undef

  .. todo:: needs extensive work, probably explicit documentation of every different directive

  The LPC driver understands the following preprocessor directives:

  ``#include, #define, #if, #ifdef, #ifndef, #else, #elif, #endif, #undef``
    same as in ANSI C

  ``#line <num>``
    line numbers start at *num* with the next line

  ``#echo``
    the rest of the line is printed to the error output (stderr), thus can be captured into a log file

  ``#pragma``
    see the separate :syntax:`pragma` page

  .. seealso:: :syntax:`pragma`, :topic:`predefined`