henry was once rumoured to have said:
>    Dear List:
>     
>        I am a learner of C ;
>    I found a  strange use of pre-processor:
>    #if 0
>    statement_A
>    #else
>    statement_B
>    #endif
>     
>    it's as follows  to me :
>     
>    #if  False
>    statement_A
>    #else                    ==> statement_B
>    statement_B
>    #endif
>     
>    Could you shed some light on it ? thanks!


This isn't exactly strange - its actually quite common.

This is usually used to comment out old blocks of code so they can be
easily reinstated if somebody changes their mind.

#if 0 / #endif is used instead of C comments because C comments don't
nest.

C.
-- 
--==============================================--
  Crossfire      | This email was brought to you
  [EMAIL PROTECTED] | on 100% Recycled Electrons
--==============================================--
-- 
SLUG - Sydney Linux User's Group - http://slug.org.au/
More Info: http://lists.slug.org.au/listinfo/slug

Reply via email to