FFI::C::UnionDef(3pm)

💖 FFI::C::UnionDef 💖

okay so bestie, welcome to the FFI::C::UnionDef page — it's a 3pm page from the User Contributed Perl Documentation, and it's literally about making C union defs happen in Perl. no cap.

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✨ VERSION ✨

version 0.15 — yes queen, that's the one.

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🌈 SYNOPSIS 🌈

so first, in your C code, you'd be doing something like this:

#include <stdint.h>
#include <stdio.h>

typedef union {
  uint8_t  u8;
  uint16_t u16;
  uint32_t u32;
} anyint_t;

void
print_anyint_as_u32(anyint_t *any)
{
  printf("0x%x\n", any->u32);
}

and then over in your Perl code, the whole vibe is:

use FFI::Platypus 1.00;
use FFI::C::UnionDef;

my $ffi = FFI::Platypus->new( api => 1 );
# See FFI::Platypus::Bundle for how bundle works.
$ffi->bundle;

my $def = FFI::C::UnionDef->new(
  $ffi,
  name => 'anyint_t',
  class => 'AnyInt',
  members => [
    u8  => 'uint8',
    u16 => 'uint16',
    u32 => 'uint32',
  ],
);

$ffi->attach( print_anyint_as_u32 => ['anyint_t'] );

my $int = AnyInt->new({ u8 => 42 });
print_anyint_as_u32($int);  # 0x2a on Intel,

and if you're like "what's a bundle" — go read FFI::Platypus::Bundle, it explains the whole thing 🫶

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🦋 DESCRIPTION 🦋

okay so this class? it creates a def for a C union. that's the whole gig. it's giving "small but mighty" ✨

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💅 CONSTRUCTOR 💅

new

my $def = FFI::C::UnionDef->new(%opts);
my $def = FFI::C::UnionDef->new($ffi, %opts);

for the standard def options, go peek at FFI::C::Def — that's where the rest of the lore lives 💜

members

this one should be an array reference stuffed with name, type pairs. and here's the cute part: for a union, the order doesn't matter. no drama, no ranking, everyone's equal 💖

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🎀 METHODS 🎀

create

my $instance = $def->create;
my $instance = $def->class->new;          # if class was specified
my $instance = $def->create(\%init);
my $instance = $def->class->new(\%init);  # if class was specified

this makes an instance of the union and hands you back an FFI::C::Union. icon behavior, honestly 👑

and you can optionally initialize member values with %init if you're feeling fancy 💅

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👀 SEE ALSO 👀

the whole friend group, go say hi:

• FFI::C
• FFI::C::Array
• FFI::C::ArrayDef
• FFI::C::Def
• FFI::C::File
• FFI::C::PosixFile
• FFI::C::Struct
• FFI::C::StructDef
• FFI::C::Union
• FFI::C::UnionDef
• FFI::C::Util
• FFI::Platypus::Record

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🌸 AUTHOR 🌸

Graham Ollis <plicease@cpan.org> — we stan 🫶

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⭐ COPYRIGHT AND LICENSE ⭐

This software is copyright (c) 2020-2022 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.

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and that's the whole page bestie!! this one's perl v5.36.0, dated 2023-02-06, and it's the FFI::C::UnionDef(3pm) page — go forth and union, ily, bye 💖✨🧚