On Thu, May 16, 2013 at 10:30:26AM +0200, Takashi Iwai wrote:
At Wed, 15 May 2013 19:11:46 +0200, Jordi Mallach wrote:
From: Steve Langasek steve.langasek@canonical.com
The arcam-av module uses libpthread, so it should pass -pthread explicitly when building in order to avoid leaving any undefined symbols or missing symbol versioning info.
Signed-off-by: Jordi Mallach jordi@debian.org
arcam-av/Makefile.am | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arcam-av/Makefile.am b/arcam-av/Makefile.am index 5c7855f..eeb2e90 100644 --- a/arcam-av/Makefile.am +++ b/arcam-av/Makefile.am @@ -3,7 +3,7 @@ asound_module_ctl_arcam_av_LTLIBRARIES = libasound_module_ctl_arcam_av.la asound_module_ctl_arcam_avdir = @ALSA_PLUGIN_DIR@
AM_CFLAGS = -Wall -g @ALSA_CFLAGS@ -AM_LDFLAGS = -module -avoid-version -export-dynamic -no-undefined +AM_LDFLAGS = -module -avoid-version -export-dynamic -no-undefined -pthread
Is AM_LDFLAGS the right place to add -lXXX?
No - libname_LIBADD should be used for -lXXX, otherwise it will not work with -Wl,--as-needed (which is the default in some distributions). AM_LDFLAGS comes before object files on the linker command line, and all libraries must come after object files when using -Wl,--as-needed.
But note that the option here is not -lpthread, but -pthread - this option is handled by gcc internally, and -lpthread is added at the same place as -lc in the actual linker command line, so -pthread will work even in AM_LDFLAGS (at least while only C is used - libtool is known to mishandle -pthread when linking C++ shared libraries).
Also the current pthread usage in alsa-plugins is inconsistent:
$ find -name Makefile.am -print0 | xargs -r0 grep -i PTHREAD -- ./pulse/Makefile.am:AM_CFLAGS = -Wall -g @ALSA_CFLAGS@ $(PTHREAD_CFLAGS) $(pulseaudio_CFLAGS) -D_GNU_SOURCE ./pulse/Makefile.am:libasound_module_pcm_pulse_la_LIBADD = @ALSA_LIBS@ $(PTHREAD_LIBS) $(pulseaudio_LIBS) ./pulse/Makefile.am:libasound_module_ctl_pulse_la_LIBADD = @ALSA_LIBS@ $(PTHREAD_LIBS) $(pulseaudio_LIBS) ./pulse/Makefile.am:libasound_module_conf_pulse_la_LIBADD = @ALSA_LIBS@ $(PTHREAD_LIBS) $(pulseaudio_LIBS) ./maemo/Makefile.am:libasound_module_pcm_alsa_dsp_la_LIBADD = @ALSA_LIBS@ $(DBUS_LIBS) -lpthread ./maemo/Makefile.am:libasound_module_ctl_dsp_ctl_la_LIBADD = @ALSA_LIBS@ $(DBUS_LIBS) -lpthread
PTHREAD_CFLAGS and PTHREAD_LIBS do not seem to be defined anywhere.