[mlpack-svn] [MLPACK] #155: order of includes and include protections

[MLPACK Trac]

#155: order of includes and include protections
--------------------------------------------------+-------------------------
  Reporter:  nslagle                              |        Owner:     
      Type:  wishlist                             |       Status:  new
  Priority:  major                                |    Milestone:     
 Component:  MLPACK                               |   Resolution:     
  Keywords:  includes, templates, style, nitpick  |     Blocking:     
Blocked By:                                       |  
--------------------------------------------------+-------------------------

Comment (by nslagle):

 A better way to guard against improper inclusion is to define a macro in
 the standard ''.hpp'' as follows:

 {{{
 #ifndef DO_STUFF_EVER_HPP
 #define DO_STUFF_EVER_HPP

 class DoStuffEver
 {
 ...
 };

 #define USE_DO_STUFF_EVER_IMPL
 #include "do_stuff_ever_impl.hpp"
 #undef USE_DO_STUFF_EVER_IMPL
 #endif
 }}}

 In the ''do_stuff_ever_impl.hpp'', add a check for the single use
 ''#define'' from above:

 {{{
 #ifndef DO_STUFF_EVER_HPP
 #ifndef USE_DO_STUFF_EVER_IMPL
 #error "Do not include this file directly."
 #endif
 #endif

 #ifndef DO_STUFF_EVER_IMPL_HPP
 #define DO_STUFF_EVER_IMPL_HPP
 ...
 #endif
 }}}

-- 
Ticket URL: <http://trac.research.cc.gatech.edu/fastlab/ticket/155#comment:2>
MLPACK <www.fast-lab.org>
MLPACK is an intuitive, fast, and scalable C++ machine learning library developed by the FASTLAB at Georgia Tech under Dr. Alex Gray.