1FFI::Platypus::ConstantU(s3e)r Contributed Perl DocumentaFtFiIo:n:Platypus::Constant(3)
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NAME

6       FFI::Platypus::Constant - Define constants in C space for Perl
7

VERSION

9       version 1.10
10

SYNOPSIS

12       "ffi/foo.c":
13
14        #include <ffi_platypus_bundle.h>
15
16        void
17        ffi_pl_bundle_constant(const char *package, ffi_platypus_constant_t *c)
18        {
19          c->set_str("FOO", "BAR");       /* sets $package::FOO to "BAR" */
20          c->set_str("ABC::DEF", "GHI");  /* sets ABC::DEF to GHI        */
21        }
22
23       "lib/Foo.pm":
24
25        package Foo;
26
27        use strict;
28        use warnings;
29        use FFI::Platypus;
30        use base qw( Exporter );
31
32        my $ffi = FFI::Platypus->new;
33        # sets constatns Foo::FOO and ABC::DEF from C
34        $ffi->bundle;
35
36        1;
37

DESCRIPTION

39       The Platypus bundle interface (see FFI::Platypus::Bundle) has an entry
40       point "ffi_pl_bundle_constant" that lets you define constants in Perl
41       space from C.
42
43        void ffi_pl_bundle_constant(const char *package, ffi_platypus_constant_t *c);
44
45       The first argument "package" is the name of the Perl package.  The
46       second argument "c" is a struct with function pointers that lets you
47       define constants of different types.  The first argument for each
48       function is the name of the constant and the second is the value.  If
49       "::" is included in the constant name then it will be defined in that
50       package space.  If it isn't then the constant will be defined in
51       whichever package called "bundle".
52
53       set_str
54            c->set_str(name, value);
55
56           Sets a string constant.
57
58       set_sint
59            c->set_sint(name, value);
60
61           Sets a 64-bit signed integer constant.
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63       set_uint
64            c->set_uint(name, value);
65
66           Sets a 64-bit unsigned integer constant.
67
68       set_double
69            c->set_double(name, value);
70
71           Sets a double precision floating point constant.
72
73   Example
74       Suppose you have a header file "myheader.h":
75
76        #ifndef MYHEADER_H
77        #define MYHEADER_H
78
79        #define MYVERSION_STRING "1.2.3"
80        #define MYVERSION_MAJOR 1
81        #define MYVERSION_MINOR 2
82        #define MYVERSION_PATCH 3
83
84        enum {
85          MYBAD = -1,
86          MYOK  = 1
87        };
88
89        #define MYPI 3.14
90
91        #endif
92
93       You can define these constants from C:
94
95        #include <ffi_platypus_bundle.h>
96        #include "myheader.h"
97
98        void ffi_pl_bundle_constant(const char *package, ffi_platypus_constant_t *c)
99        {
100          c->set_str("MYVERSION_STRING", MYVERSION_STRING);
101          c->set_uint("MYVERSION_MAJOR", MYVERSION_MAJOR);
102          c->set_uint("MYVERSION_MINOR", MYVERSION_MINOR);
103          c->set_uint("MYVERSION_PATCH", MYVERSION_PATCH);
104          c->set_sint("MYBAD", MYBAD);
105          c->set_sint("MYOK", MYOK);
106          c->set_double("MYPI", MYPI);
107        }
108
109       Your Perl code doesn't have to do anything when calling bundle:
110
111        package Const;
112
113        use strict;
114        use warnings;
115        use FFI::Platypus;
116
117        {
118          my $ffi = FFI::Platypus->new( api => 1 );
119          $ffi->bundle;
120        }
121
122        1;
123

AUTHOR

125       Author: Graham Ollis <plicease@cpan.org>
126
127       Contributors:
128
129       Bakkiaraj Murugesan (bakkiaraj)
130
131       Dylan Cali (calid)
132
133       pipcet
134
135       Zaki Mughal (zmughal)
136
137       Fitz Elliott (felliott)
138
139       Vickenty Fesunov (vyf)
140
141       Gregor Herrmann (gregoa)
142
143       Shlomi Fish (shlomif)
144
145       Damyan Ivanov
146
147       Ilya Pavlov (Ilya33)
148
149       Petr Pisar (ppisar)
150
151       Mohammad S Anwar (MANWAR)
152
153       Håkon Hægland (hakonhagland, HAKONH)
154
155       Meredith (merrilymeredith, MHOWARD)
156
157       Diab Jerius (DJERIUS)
158

160       This software is copyright (c) 2015,2016,2017,2018,2019 by Graham
161       Ollis.
162
163       This is free software; you can redistribute it and/or modify it under
164       the same terms as the Perl 5 programming language system itself.
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168perl v5.30.1                      2020-02-06        FFI::Platypus::Constant(3)
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