FFI::Platypus::Constant(3)

NAME
FFI::Platypus::Constant - Define constants in C space for Perl

VERSION
version 2.10

SYNOPSIS
"ffi/foo.c":

 #include <ffi_platypus_bundle.h>

 void
 ffi_pl_bundle_constant(const char *package, ffi_platypus_constant_t *c)
 {
   c->set_str("FOO", "BAR");       /* sets $package::FOO to "BAR" */
   c->set_str("ABC::DEF", "GHI");  /* sets ABC::DEF to GHI        */
 }

"lib/Foo.pm":

 package Foo;

 use strict;
 use warnings;
 use FFI::Platypus 2.00;
 use Exporter qw( import );

 my $ffi = FFI::Platypus->new( api => 2 );
 # sets constants Foo::FOO and ABC::DEF from C
 $ffi->bundle;

 1;

DESCRIPTION
The Platypus bundle interface (see FFI::Platypus::Bundle) has an entry point "ffi_pl_bundle_constant" that lets you define constants in Perl space from C.

 void ffi_pl_bundle_constant(const char *package, ffi_platypus_constant_t *c);

The first argument "package" is the name of the Perl package. The second argument "c" is a struct with function pointers that lets you define constants of different types. The first argument for each function is the name of the constant and the second is the value. If "::" is included in the constant name then it will be defined in that package space. If it isn't then the constant will be defined in whichever package called "bundle".

set_str
     c->set_str(name, value);

    Sets a string constant.

set_sint
     c->set_sint(name, value);

    Sets a 64-bit signed integer constant.

set_uint
     c->set_uint(name, value);

    Sets a 64-bit unsigned integer constant.

set_double
     c->set_double(name, value);

    Sets a double precision floating point constant.

  Example
Suppose you have a header file "myheader.h":

 #ifndef MYHEADER_H
 #define MYHEADER_H

 #define MYVERSION_STRING "1.2.3"
 #define MYVERSION_MAJOR 1
 #define MYVERSION_MINOR 2
 #define MYVERSION_PATCH 3

 enum {
   MYBAD = -1,
   MYOK  = 1
 };

 #define MYPI 3.14

 #endif

You can define these constants from C:

 #include <ffi_platypus_bundle.h>
 #include "myheader.h"

 void ffi_pl_bundle_constant(const char *package, ffi_platypus_constant_t *c)
 {
   c->set_str("MYVERSION_STRING", MYVERSION_STRING);
   c->set_uint("MYVERSION_MAJOR", MYVERSION_MAJOR);
   c->set_uint("MYVERSION_MINOR", MYVERSION_MINOR);
   c->set_uint("MYVERSION_PATCH", MYVERSION_PATCH);
   c->set_sint("MYBAD", MYBAD);
   c->set_sint("MYOK", MYOK);
   c->set_double("MYPI", MYPI);
 }

Your Perl code doesn't have to do anything when calling bundle:

 package Const;

 use strict;
 use warnings;
 use FFI::Platypus 2.00;

 {
   my $ffi = FFI::Platypus->new( api => 2 );
   $ffi->bundle;
 }

 1;

AUTHOR
Author: Graham Ollis <plicease@cpan.org>

Contributors:

Bakkiaraj Murugesan (bakkiaraj)

Dylan Cali (calid)

pipcet

Zaki Mughal (zmughal)

Fitz Elliott (felliott)

Vickenty Fesunov (vyf)

Gregor Herrmann (gregoa)

Shlomi Fish (shlomif)

Damyan Ivanov

Ilya Pavlov (Ilya33)

Petr Písař (ppisar)

Mohammad S Anwar (MANWAR)

Håkon Hægland (hakonhagland, HAKONH)

Meredith (merrilymeredith, MHOWARD)

Diab Jerius (DJERIUS)

Eric Brine (IKEGAMI)

szTheory

José Joaquín Atria (JJATRIA)

Pete Houston (openstrike, HOUSTON)

Lukas Mai (MAUKE)

COPYRIGHT AND LICENSE
This software is copyright (c) 2015-2022 by Graham Ollis.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.