/ 
Alt-FFI-Raw-Platypus-0.04
River stage zero No dependents
/ FFI::Raw::MemPtr

NAME

FFI::Raw::MemPtr - FFI::Platypus::Legacy::Raw memory pointer type

VERSION

version 0.04

DESCRIPTION

A FFI::Raw::MemPtr represents a memory pointer which can be passed to functions taking a FFI::Raw::ptr argument.

The allocated memory is automatically deallocated once the object is not in use anymore.

CONSTRUCTORS

new

FFI::Raw::MemPtr->new( $length );

Allocate a new FFI::Raw::MemPtr of size $length bytes.

new_from_buf

my $memptr = FFI::Platypus::Legacy::Raw::MemPtr->new_from_buf( $buffer, $length );

Allocate a new FFI::Platypus::Legacy::Raw::MemPtr of size $length bytes and copy $buffer into it. This can be used, for example, to pass a pointer to a function that takes a C struct pointer, by using pack() or the Convert::Binary::C module to create the actual struct content.

For example, consider the following C code

struct some_struct {
  int some_int;
  char some_str[];
};

extern void take_one_struct(struct some_struct *arg) {
  if (arg->some_int == 42)
    puts(arg->some_str);
}

It can be called using FFI::Platypus::Legacy::Raw as follows:

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

my $packed = pack('ix![p]p', 42, 'hello');
my $arg = FFI::Platypus::Legacy::Raw::MemPtr->new_from_buf($packed, length $packed);

my $take_one_struct = FFI::Platypus::Legacy::Raw->new(
  $shared, 'take_one_struct',
  FFI::Platypus::Legacy::Raw::void, FFI::Platypus::Legacy::Raw::ptr
);

$take_one_struct->($arg);

Which would print hello.

new_from_ptr

my $memptr = FFI::Platypus::Legacy::Raw::MemPtr->new_from_ptr( $ptr );

Allocate a new FFI::Platypus::Legacy::Raw::MemPtr pointing to the $ptr, which can be either a FFI::Platypus::Legacy::Raw::MemPtr or a pointer returned by another function.

This is the FFI::Platypus::Legacy::Raw equivalent of a pointer to a pointer.

METHODS

to_perl_str

my $memptr = FFI::Platypus::Legacy::Raw::MemPtr->to_perl_str;
my $memptr = FFI::Platypus::Legacy::Raw::MemPtr->to_perl_str( $length );

Convert a FFI::Platypus::Legacy::Raw::MemPtr to a Perl string. If $length is not provided, the length of the string will be computed using strlen().

AUTHOR

Graham Ollis <plicease@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2019 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.