FFI::Platypus::Legacy::Raw

Perl bindings to the portable FFI library (libffi)

SYNOPSIS

use FFI::Platypus::Legacy::Raw;

my $cos = FFI::Platypus::Legacy::Raw->new(
  'libm.so', 'cos',
  FFI::Platypus::Legacy::Raw::double, # return value
  FFI::Platypus::Legacy::Raw::double  # arg #1
);

say $cos->call(2.0);

DESCRIPTION

FFI::Platypus::Legacy::Raw and friends are a fork of FFI::Raw that uses FFI::Platypus instead of FFI::Raw's own libffi implementation. It is intended for use when migrating from FFI::Raw to FFI::Platypus. The main reason one might have for switching from Raw to Platypus is because Platypus is actively maintained, provides a more powerful interface, can be much faster when functions are "attached", and works on more platforms than Raw. This module should be a drop in replacement for FFI::Raw, simply replace all instances of FFI::Raw to FFI::Platypus::Legacy::Raw. See also Alt::FFI::Raw::Platypus for a way to use this module without making any source code changes.

FFI::Platypus::Legacy::Raw provides a low-level foreign function interface (FFI) for Perl based on libffi. In essence, it can access and call functions exported by shared libraries without the need to write C/XS code.

Dynamic symbols can be automatically resolved at runtime so that the only information needed to use FFI::Platypus::Legacy::Raw is the name (or path) of the target library, the name of the function to call and its signature (though it is also possible to pass a function pointer obtained, for example, using DynaLoader).

Note that this module has nothing to do with FFI.

CONSTRUCTORS

new

my $ffi = FFI::Platypus::Legacy::Raw->new( $library, $function, $return_type, @arg_types )

Create a new FFI::Platypus::Legacy::Raw object. It loads $library, finds the function $function with return type $return_type and creates a calling interface.

If $library is undef then the function is searched in the main program.

This method also takes a variable number of types, representing the arguments of the wanted function.

new_from_ptr

my $ffi = FFI::Platypus::Legacy::Raw->new_from_ptr( $function_ptr, $return_type, @arg_types )

Create a new FFI::Platypus::Legacy::Raw object from the $function_ptr function pointer.

This method also takes a variable number of types, representing the arguments of the wanted function.

METHODS

call

my $ret = $ffi->call( @args)

Execute the FFI::Platypus::Legacy::Raw function. This method also takes a variable number of arguments, which are passed to the called function. The argument types must match the types passed to new (or new_from_ptr).

The FFI::Platypus::Legacy::Raw object can be used as a CODE reference as well. Dereferencing the object will work just like call():

$cos->call(2.0); # normal call() call
$cos->(2.0);     # dereference as CODE ref

This works because FFI::Platypus::Legacy::Raw overloads the &{} operator.

coderef

my $code = FFI::Platypus::Legacy::Raw->coderef;

Return a code reference of a given FFI::Platypus::Legacy::Raw.

SUBROUTINES

memptr

my $memptr = FFI::Platypus::Legacy::Raw::memptr( $length );

Create a FFI::Platypus::Legacy::Raw::MemPtr. This is a shortcut for FFI::Platypus::Legacy::Raw::MemPtr->new(...).

callback

my $callback = FFI::Platypus::Legacy::Raw::callback( $coderef, $ret_type, \@arg_types );

Create a FFI::Platypus::Legacy::Raw::Callback. This is a shortcut for FFI::Platypus::Legacy::Raw::Callback->new(...).

TYPES

Caveats on the way types were defined by the original FFI::Raw:

This module uses the common convention that char is 8 bits, short is 16 bits, int is 32 bits, long is 32 bits on a 32bit arch and 64 bits on a 64 bit arch, int64 is 64 bits. While this is probably true on most modern platforms (if not all), it isn't technically guaranteed by the standard. FFI::Platypus itself, differs in that int, long, etc are the native sizes, even if they do not follow this common convention and you need to use sint32, sint64, etc if you want a specific sized type.

This module also assumes that char is signed. Although this is commonly true on many platforms it is not guaranteed by the standard. On Windows, for example the char type is unsigned. FFI::Platypus by contrast follows to the standard where char uses the native behavior, and if you want an signed character type you can use sint8 instead.

void

my $type = FFI::Platypus::Legacy::Raw::void();

Return a FFI::Platypus::Legacy::Raw void type.

int

my $type = FFI::Platypus::Legacy::Raw::int();

Return a FFI::Platypus::Legacy::Raw integer type.

uint

my $type = FFI::Platypus::Legacy::Raw::uint();

Return a FFI::Platypus::Legacy::Raw unsigned integer type.

short

my $type = FFI::Platypus::Legacy::Raw::short();

Return a FFI::Platypus::Legacy::Raw short integer type.

ushort

my $type = FFI::Platypus::Legacy::Raw::ushort();

Return a FFI::Platypus::Legacy::Raw unsigned short integer type.

long

my $type = FFI::Platypus::Legacy::Raw::long();

Return a FFI::Platypus::Legacy::Raw long integer type.

ulong

my $type = FFI::Platypus::Legacy::Raw::ulong();

Return a FFI::Platypus::Legacy::Raw unsigned long integer type.

int64

my $type = FFI::Platypus::Legacy::Raw::int64();

Return a FFI::Platypus::Legacy::Raw 64 bit integer type. This requires Math::Int64 to work.

uint64

my $type = FFI::Platypus::Legacy::Raw::uint64();

Return a FFI::Platypus::Legacy::Raw unsigned 64 bit integer type. This requires Math::Int64 to work.

char

my $type = FFI::Platypus::Legacy::Raw::char();

Return a FFI::Platypus::Legacy::Raw char type.

uchar

my $type = FFI::Platypus::Legacy::Raw::uchar();

Return a FFI::Platypus::Legacy::Raw unsigned char type.

float

my $type = FFI::Platypus::Legacy::Raw::float();

Return a FFI::Platypus::Legacy::Raw float type.

double

my $type = FFI::Platypus::Legacy::Raw::double();

Return a FFI::Platypus::Legacy::Raw double type.

str

my $type = FFI::Platypus::Legacy::Raw::str();

Return a FFI::Platypus::Legacy::Raw string type.

ptr

my $type = FFI::Platypus::Legacy::Raw::ptr();

Return a FFI::Platypus::Legacy::Raw pointer type.

EXTENSIONS

Documented in this section are features that are available when using FFI::Platypus::Legacy::Raw, but are NOT provided by FFI::Raw. Only use them if you do not intend on switching back to FFI::Raw.

attach

$ffi->attach;  # allowed for functions specified by name
               # but not by address/pointer
$ffi->attach($name);
$ffi->attach($name, $prototype);

Attach the function as an xsub. This is probably the most important feature that FFI::Platypus provides that FFI::Raw does not. calling an attached xsub is much faster than calling an unattached function.

platypus

my $ffi = FFI::Platypus::Legacy::Raw->platypus($library);

Returns the FFI::Platypus instance used internally by this module. This can be useful to customize for your particular library. Adding types can be useful.

my $lib = 'libfoo.so';
my $ffi = FFI::Platypus::Legacy::Raw->platypus($lib);
$ffi->type('int[42]' => 'my_int_42');
my $f = FFI::Platypus::Legacy::Raw->new(
  $lib, 'my_array_sum',
  'int', 'my_int_64',
);
my $sum = $f->call([1..42]);

You CANNOT get the platypus instance for undef (libc and other codes already linked into the currently running Perl) using this interface, as that is somewhat "global" and adding types or other customizations there could break other modules.

mix and match types

You can mix and match FFI::Raw and FFI::Platypus types. The main benefit is that you get the more rigorous type system as described above in the TYPES caveat.

There is an overhead to the FFI::Platypus::Legacy:Raw::ptr type in order to handle the various pointer types ( FFI::Platypus::Legacy::Raw::Ptr, FFI::Platypus::Legacy::Raw::MemPtr, FFI::Platypus::Legacy::Raw::Callback). If you aren't using those classes, then you can save a few cycles by instead using the Platypus opaque type.

SEE ALSO

FFI::Platypus, Alt::FFI::Raw::Platypus

AUTHOR

Original author: Alessandro Ghedini (ghedo, ALEXBIO)

Current maintainer: Graham Ollis [email protected]

Contributors:

Bakkiaraj Murugesan (bakkiaraj)

Dylan Cali (CALID)

Brian Wightman (MidLifeXis, MLX)

David Steinbrunner (dsteinbrunner)

Olivier Mengué (DOLMEN)

COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Alessandro Ghedini.

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