Actually on close inspection it looks like open is succeeding. Not sure what's going on here. Here's more of the strace:

open("/usr/lib/i386-linux-gnu/alsa-lib/libasound_module_pcm_adt_dsp.so", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\20\7\0\0004\0\0\0"..., 512) = 512 fstat64(3, {st_mode=S_IFREG|0644, st_size=7655, ...}) = 0 mmap2(NULL, 8464, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x166000 mmap2(0x167000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0) = 0x167000 close(3) = 0 munmap(0x166000, 8464) = 0 write(2, "ALSA lib dlmisc.c:254:(snd1_dlob"..., 45ALSA lib dlmisc.c:254:(snd1_dlobj_cache_get) ) = 45 write(2, "Cannot open shared library /usr/"..., 91Cannot open shared library /usr/lib/i386-linux-gnu/alsa-lib/libasound_module_pcm_adt_dsp.so) = 91

Any insight?

-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Friday, June 13, 2014 8:42 AM To: Brandon Yates Cc: alsa-devel@alsa-project.org Subject: Re: [alsa-devel] Plug In Creation - aplay can't find existing .so

At Tue, 10 Jun 2014 13:55:39 -0400, Brandon Yates wrote:

Hello,

I am working on a new pcm plugin. At this point it is basically just a

Hello World plugin, to make sure I have the tools working and understand the workflow. I created a simple file which is just

basically:

#include <alsa/asoundlib.h> #include <alsa/pcm_external.h> SND_PCM_PLUGIN_DEFINE_FUNC(my_mod) { printf("hello world\n"); return 0; } SND_PCM_PLUGIN_SYMBOL(my_mod);

I compiled this as a shared lib named

'libasound_module_pcm_my_mod.so'

and copied it to '/usr/lib/i386-linux-gnu/alsa-lib/'

I edited my ~/.asoundrc to create a new device that uses this plugin. Then I try to use it with `aplay --device=my_mod_test out.pcm`

I get the error message

ALSA lib dlmisc.c:254:(snd1_dlobj_cache_get) Cannot open shared library /usr/lib/i386-linux-gnu/alsa-lib/libasound_module_pcm_my_mod.so aplay: main:682: audio open error: No such device or address

But this file actually does exist, I just copied it there.

Any idea why this happens?

Try strace to see what happens. If it fails in dlopen(), it's likely because your shared object is invalid.

Takashi