When I started with Perl in the previous century, one of its highlights was its use as a "glue" language, and its ability to make simple things easy. GD is the first I recall, later I had fun with the inevitable DBI, did some work with XML::LibXML and a lot of others I am to lazy to recall right now. Then came THE WEB and Perl developers (including me) seem to have changed their focus (and also: Many new developers solved web problems using Perl). In the last two years, when I played with 3D graphics and sound, I was a bit disappointed about the amount of stale / abandoned CPAN modules in that area. I was able to use Audio::PortAudio (most recent release in January 2007) to record sound from my microphone, but only after suppressing a bunch of warnings, and I was surprised that it worked at all.
Looking for a contemporary way to do sound on Linux, I stumbled over PipeWire. It comes with a set of CLI commands, decent documentation, and a tutorial in C. I want to do two things: 1) record and play sound without shelling out to an external program, and 2) detect whether a microphone is actually plugged in so that I can enable/disable the "record" button in my GUI accordingly. But like many "modern" C libraries, PipeWire utterly sucks at making simple things easy. So I thought: How hard can it be to use that library from Perl?
I am not at all an expert in this area. I have not used C since about 20 years and never tried XS programming. I have heard good things about FFI::Platypus, so I thought I would give it a try. It turned out to be a roller coaster of success and failures.
FFI::Platypus does not really support several constructs used by the library (dynamically sized arrays of structs, callbacks returning pointers to a struct, ...). I also need to manually copy-write every single struct in terms of FFI::Platypus (or FFI::C) which stops to be fun after the first two dozen structs. The (very good, BTW) docs point to Convert::Binary::C for these things, so I added that to the mix. I found that it didn't handle current C compilers (the maintainer has fixed this on GitHub, no CPAN release yet) and can not handle many of PipeWire's header files because they make heavy use of GCC extensions. I also learned that Convert::Binary::C is in "bugfix-only" state. I have segfaults (same thing as these) which suggest that the Perl we get from Linux distributions can not handle the library at all, so I build my own Perl for this experiment.
Of course, there's also the XS route, and Dave Mitchell has announced his plan to Rewrite the XS pod files. I am somewhat impatient to see this, but as far as I know the tedious task of re-writing every struct (called "typemaps" in XS) isn't much easier than doing it with FFI::Platypus.
My current route is to use Convert::Binary::C to auto-generate Perl classes equivalent to the C structs. This is actually fun, but also time consuming and I am afraid that I get lost in abstractions over abstractions and never get to actually use the Perl library.
So, while I am still making progress, I wonder: Are there other developers around who work with C libraries these days? How do they do it? Or is this an art soon to be obsolete?
In reply to What's the "modern" way to talk to C libraries? by haj
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