Re: Build system cleanup

["Måns Rullgård" <mans@mansr.com>]

Jan Stary <hans@stare.cz> writes:

>> > checking for strdup... yes
>> >
>> > 	Not specific to NetBSD of course, but why are we running these
>> > 	tests (taking strdup as a random example)? Is there a POSIX
>> > 	system without strdup? And if we miss strdup, then what?
>> > 	With that configure.ac line changed to check for xstrdup instead,
>> > 	this will just become
>> >
>> > 		checking for xstrdup... no
>> >
>> > 	but everyting follows as before. Which means we have checked for
>> > 	a function (via AC_CHECK_FUNCS), found out it does not exist,
>> > 	and ignored the result. What is that for?
>> 
>> I already explained this about five times.
>
> The only explanation I have seen so far is
> "it was warranted in the olden days". Perhaps it was;
> but why are we checking for e.g. strdup() in 2020
> (and ingoring the result of AC_CHECK_FUNCS anyway)?

It's there because I haven't got around to removing it yet.  It's
harmless for now.

>> > checking for sys/soundcard.h... yes
>> >
>> > 	On NetBSD, sys/soundcard.h says
>> >
>> > 		This is an OSS (Linux) audio emulator.
>> >  		Use the Native NetBSD API for developing new code,
>> > 		and this only for compiling Linux programs.
>> >
>> > 	The check is
>> >
>> > 	SOX_FMT_HEADERS([oss], [sys/soundcard.h], [SOUND_MIXER_MUTE],
>> > 		[], [devices])
>> >
>> > 	so at least we correctly recognize this as OSS emulation.
>> > 	But the check does not work universaly: NetBSD has
>> > 	/usr/include/sys/soundcard.h -> ../soundcard.h, but e.g.
>> > 	OpenBSD only has /usr/include/soundcard.h (same code though).
>> > 	Apparently, the name makes a difference:
>> > 	a test for "sys/soundcard.h" will fail on OpenBSD.
>> >
>> > checking whether SOUND_MIXER_MUTE is declared... no
>> >
>> > 	Why SOUND_MIXER_MUTE, specificaly, out of all the others?
>> > 	For example, SOUND_MIXER_INFO is declared, which would
>> > 	make the oss emulation detected (not saying this is
>> > 	the correct test).
>> >
>> > 	Lastly, oss requires a library to be linked:
>> > 	https://netbsd.gw.com/cgi-bin/man-cgi?ossaudio
>> > 	That would be /usr/lib/libossaudio.so - I believe a recent
>> > 	commit has concluded that oss does not require any library
>> > 	(being a bunch of defined ioctls); on NetBSD, it maybe does.
>> >
>> > 	$ nm /usr/lib/libossaudio.so | grep oss
>> > 	0000000000001f60 T _oss_ioctl
>> 
>> Real OSS does _not_ need a library.  That is _only_ used for the
>> incomplete emulation that we don't want.  The test is chosen such that
>> it passes on Linux, FreeBSD, and Solaris while failing on NetBSD and
>> OpenBSD.
>
> In case it is intended to detect OSS as not present
> on OpenBSD and NetBSD (who only emulate OSS),
> it seems to work as intended.

That was the intention.

>> > checking for sys/audioio.h... yes
>> >
>> > 	This seems to be NetBSD's native audio interface.
>> > 	https://netbsd.gw.com/cgi-bin/man-cgi?audio
>> > 	It's what the NetBSD port of SoX uses:
>> > 	http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/audio/sox/
>> >
>> > checking whether AUDIO_HWFEATURE_DUPLEX is declared... no
>> >
>> > 	... but we miss that, because of this.
>> > 	It seems NetBSD's audio system came from Sun audio
>> > 	(/usr/pkg/bin/sox reports AUDIO DEVICE DRIVERS: sunau),
>> > 	but it's not quite the same; in particular,
>> > 	AUDIO_HWFEATURE_DUPLEX is not defined.
>> 
>> Already fixed.
>
> The detectin works, thanks:
>
> Audio devices:
>   alsa                    no
>   ao                      no
>   coreaudio               no
>   oss                     no
>   pulseaudio              no
>   sndio                   no
>   sunaudio                yes
>   waveaudio               no
>
> It doesn't actually play though:
>
> $ play -V -n -b 16 synth 1
> play INFO sunaudio: Sun Audio driver only supports bytes and words
> play:	   SoX v14.4.2
> play INFO nulfile: sample rate not specified; using 48000
>
> Input File     : '' (null)
> Channels       : 1
> Sample Rate    : 48000
> Precision      : 32-bit
>
> Output File    : 'default' (sunau)
> Channels       : 1
> Sample Rate    : 48000
> Precision      : 16-bit
> Sample Encoding: 16-bit Signed Integer PCM
> Endian Type    : little
> Reverse Nibbles: no
> Reverse Bits   : no
>
> play INFO sox: effects chain: input	   48000Hz  1 channels
> play INFO sox: effects chain: synth	   48000Hz  1 channels
> play INFO sox: effects chain: dither	   48000Hz  1 channels
> play INFO sox: effects chain: output	   48000Hz  1 channels
> In:0.00% 00:00:00.00 [00:00:00.00] Out:0     [	    |	   ]	    Clip:0    Memory fault (core dumped)

Already fixed.

-- 
Måns Rullgård


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