32-bit versions¹ seem to be ok.  Both 0.71 and 0.72 print (consistently):

9175224
4194672
[download]

While I was at it, I also tried a few more 64-bit versions on other machines (5.10.0, 5.10.1, 5.12.2²). All exhibited the same wonkiness mentioned earlier. So it clearly seems to be a 64-bit incompatibility.

Two more notes:

(1)  In your Makefile.PL you have a line

  LIBS => $Config{cc} eq 'gcc' || $Config{cc} eq 'cc' ? ['-lstdc++'] :
+ '',
[download]

With some of the perls I had tried, $Config{cc} was set to an absolute path '/usr/local/bin/gcc', or to 'gcc ' (yes, with a trailing space - not sure where this came from, I didn't knowingly put it there). So, your check didn't match, and libstdc++ wasn't linked in, which in turn led to the usual undefined reference to '__gxx_personality_v0' when Dynaloader tried to load the .so file.

Something like the following might be slightly more robust:

  LIBS => $Config{cc} =~ /\bg?cc\s*$/ ? ['-lstdc++'] : '',
[download]

(2)  When trying to build Devel-Size-0.72 for 5.12.2 with a more recent and picky gcc (v4.3.2), I got the following errors:

Size.xs: In function 'UV thing_size(const SV*, char* (*)[8192])':
Size.xs:552: error: invalid conversion from 'const void*' to 'void*'
Size.xs:553: error: invalid conversion from 'const void*' to 'void*'
Size.xs:554: error: invalid conversion from 'const void*' to 'void*'
make: *** [Size.o] Error 1
[download]

Explicitly casting thing to non-const void* 'fixed' it:

    /* Is there something hanging off the arylen element? */
    if (AvARYLEN((void*)thing)) {
      if (check_new(tv, AvARYLEN((void*)thing))) {
    total_size += thing_size(AvARYLEN((void*)thing), tv);
[download]

__________

And here the 'perl -V's, just in case:

¹⁾

²⁾

64-bit bug now fixed and will be on CPAN once I've had it tested on *nix and regression on 32-bit builds.

c:\test>perl -MDevel::Size71=total_size 
-E"$a[$_]=1 for 1..1e6; say total_size( \@a )"
32388768

c:\test>perl -MDevel::Size=total_size 
-E"$a[$_]=1 for 1..1e6; say total_size( \@a )"
32388768

c:\test>perl -MDevel::Size71=total_size 
-E"$a[$_]=[1,1] for 1..5e5; say total_size( \@a )"
104194464

c:\test>perl -MDevel::Size=total_size 
-E"$a[$_]=[1,1] for 1..5e5; say total_size( \@a )"
104194464
[download]

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