Filter::cpp(3) User Contributed Perl Documentation Filter::cpp(3)

NAME
       Filter::cpp - cpp source filter

SYNOPSIS
           use Filter::cpp ;

DESCRIPTION
       This source filter pipes the current source file through the C pre-
       processor (cpp) if it is available.

       As with all source filters its scope is limited to the current source
       file only. Every file you want to be processed by the filter must have
       a

           use Filter::cpp ;

       near the top.

       Here is an example script which uses the filter:

           use Filter::cpp ;

           #define FRED 1
           $a = 2 + FRED ;
           print "a = $a\n" ;
           #ifdef FRED
           print "Hello FRED\n" ;
           #else
           print "Where is FRED\n" ;
           #endif

       And here is what it will output:

           a = 3
           Hello FRED

       This example below, provided by Michael G Schwern, shows a clever way
       to get Perl to use a C pre-processor macro when the Filter::cpp module
       is available, or to use a Perl sub when it is not.

           # use Filter::cpp if we can.
           BEGIN { eval 'use Filter::cpp' }

           sub PRINT {
               my($string) = shift;

           #define PRINT($string) \
               (print $string."\n")
           }

           PRINT("Mu");

       Look at Michael's Tie::VecArray module for a practical use.

AUTHOR
       Paul Marquess

DATE
       11th December 1995.



perl v5.16.3                      2013-03-29                    Filter::cpp(3)