Filter::cpp(3pm) User Contributed Perl Documentation Filter::cpp(3pm)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 = $a
" ;
#ifdef FRED
print "Hello FRED
" ;
#else
print "Where is FRED
" ;
#endif
And here is what it will output:
a = 3
Hello FRED
This example below, provided by Michael G Schwern, shows a clever way to get Perl to use a C pre-processor macro when the Filter::cpp
module is available, or to use a Perl sub when it is not.
# use Filter::cpp if we can.
BEGIN { eval 'use Filter::cpp' }
sub PRINT {
my($string) = shift;
#define PRINT($string)
(print $string."
")
}
PRINT("Mu");
Look at Michael's Tie::VecArray module for a practical use.
AUTHOR
Paul Marquess
DATE
11th December 1995.
perl v5.14.2 2012-06-22 Filter::cpp(3pm)
Check Out this Related Man Page
cxref-cpp(1) General Commands Manual cxref-cpp(1)NAME
cxref-cpp - A modified C preprocessor to use with cxref.
SYNOPSIS
cxref-cpp ...
DESCRIPTION
To improve the output that is available for the source code for cross-referencing a modified version of the GNU CPP v2.7.2 is supplied
(named cxref-cpp).
This modified C preprocessor allows for a finer control over some features of the preprocessing that are not important for a compiler. In
a standard preprocessor, the preprocessor directives are intended for use only by the preprocessor, so passing the information through is
not important.
With cxref-cpp, there are some features that are different to the standard GNU CPP:
Compared to gcc versions earlier than version 2.8.0 there is an extra option that will output the #include lines from the source
file. In version 2.8.0 and later this option is present.
Comments trailing a #include or a #define are not preserved by all versions of gcc even if the -C option is used. This is not
important while compiling, but is useful for documenting.
The cxref-cpp program will take on the personality of the installed version of gcc so that the gcc header files can be parsed. This
means that it includes the same default include directory paths and macro definitions. The file that contains these definitions is
called cxref-cpp.defines and is installed by the cxref-cpp-configure program or specified by the -cxref-cpp-defines command line
option.
OPTIONS
The same as for gcc, apart from '-cxref-cpp-defines' described above.
SEE ALSO cxref(1), cxref-cpp-configure(1), gcc(1)
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