First you make the C data buffer available as a PV to Perl, I think via newSvPV. Depending on the documentation on who owns the memory, you don't want the memory to be freed by Perl but by your library, see the documentation on how to tell Perl to not free your PV.

Then, you can use unpack to get at the raw numbers. This will likely use the same semantics as your C compiler, which should in this case be "good enough". Beware that this might break if you transport data between machines with differing endianness or word size:

my $bps = 32;
my $fmt = 3;

my %template = (
  "32,3" => 'd',#  A double-precision float in native format.
  "32,1" => 'I',
  "32,2, => 'i',
  # ... add the other formats as you need
);

my $rawdata = get_raw_data_from_C_library();

my $t = $template{ "$bps,$fmt" }
    or die "Couldn't find an unpack template for $bps BPS, format $fmt
+";
my @samples = unpack $template, $rawdata;

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In reply to Re^3: C types and SV's by Corion
in thread C types and SV's and unpack by blakew

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