When working through https://github.com/xsawyerx/xs-fun/blob/master/chapter_01/chapter_01.pod make test initially failed with No tests defined for XSFun extension.

Re-running perl Makefile.PL after creating t/add_numbers.t got make test working.

I guess that instruction should be in chapter_01.pod.

    /* bless into the proper package */
    RETVAL = sv_bless( self, gv_stashpv( class, 0 ) );
    OUTPUT: RETVAL

https://github.com/xsawyerx/xs-fun/blame/master/chapter_03/chapter_03.pod#L170

you should use gv_stashsv instead of gv_stashpv since your input is already a SV, rurban mentioned on #p5p that strlen on the package name could produce an obj blessed into a different package than the one passed in if the package name contains nulls

First of all: Many thanks for this great tutorial.

Unfortunately the last chapter is not complete. Moreover the example code is broken.

• The code found in xs-fun/chapter_08/Audio-Chromaprint is not fully covered by chapter_08.pod
• t/leak-pointer is broken. When I run it with default values of Test::MemoryGrowth (10/10000) I get

t/leak-pointer.t .. 
1..2
ok 1 - use Audio::Chromaprint;
not ok 2 - Does not grow in memory

#   Failed test 'Does not grow in memory'
#   at t/leak-pointer.t line 11.
# Lost 344064 bytes of memory over 10000 calls, average of 34.41 per call
# Looks like you failed 1 test of 2.
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/2 subtests 

What is the line algo = SvIV( ST( i + 1 ) ); needed for?

In the appropriate file Chromaprint.xs this line is missing.

Is that a mistake?

Typemaps are a strong feature and probably the most useful one when converting C structures to Perl structures.

However, it seems difficult to grasp fully. I find myself asking numerous question after reading a single line of documentation. This should get at least one chapter.

I guess this is really a dumb question but do you have fun with XS and C++ too?
Because, I like the OpenFST library (http://www.openfst.org) and would love to see at least some bindings in Perl, but it's written in C++, not C.
XS fun in the other hand constantly talks about C++.

In Chapter 04, it is mentioned that sv_dump(value) shows that value has PADTMP in its FLAGS output. This doesn't turn up on (perlbrew-ed) perl-5.16.3, perl-5.18.2, perl-5.20.0 or perl-5.21.2 running on Debian Linux "Jessie" x86_64. Which version of perl was used to generate the output from this example? Or, another way of putting this: what did I do wrong?

When I ran 'perl Makefile.PL && make && make test' I got:

WARNING: Setting ABSTRACT via file 'lib/XSFun.pm' failed
at /System/Library/Perl/5.16/ExtUtils/MakeMaker.pm line 609.

and finally :

cc -mmacosx-version-min=10.9 -arch x86_64 -arch i386 -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector -o blib/arch/auto/XSFun/XSFun.bundle

clang: error: no input files
make: *** [blib/arch/auto/XSFun/XSFun.bundle] Error 1

I cut and pasted the file contents from the web pages, the directories and files look good, any suggestions as to what caused this? BTW, I'm new to GitHub and recently to perl, but I am an old C hand.
Thanks
Peter

• chromaprint_get_version
• chromaprint_new
• chromaprint_free
• chromaprint_get_algorithm (implement, since it's not available)
• chromaprint_set_option
• chromaprint_start
• chromaprint_feed
• chromaprint_finish
• chromaprint_get_fingerprint
• chromaprint_get_raw_fingerprint
• chromaprint_get_fingerprint_hash
• chromaprint_encode_fingerprint
• chromaprint_decode_fingerprint
• chromaprint_hash_fingerprint
• chromaprint_dealloc