NAME

SYNOPSIS

    use Filter::cpp ;

DESCRIPTION

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

DATE