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Date: Tue, 01 Jun 2004 15:27:44 +0300
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From: Martin_Storsj
Subject: Update for dynamic loading of ALSA

I sent you a patch a few months ago which enables SDL to load ALSA
dynamically. Now I've finally got time to tweak this yet some more. I've
added code from alsa.m4 (from alsa's dev package) to acinclude.m4, and
made the detection of the alsa library name a bit better. I've also
fixed up the loading versioned symbols with dlvsym, so that it falls
back to dlsym.

I wouldn't say the configure script is complete yet, but this is how far
I've come this time, and I'm no expert at those things.
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@slouken
slouken committed Aug 21, 2004
1 parent 66c1f79 commit 84521d6
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Showing 3 changed files with 184 additions and 17 deletions.
147 changes: 147 additions & 0 deletions acinclude.m4
View file
Expand Up @@ -19,6 +19,153 @@ __EOF__
cat >>$new <$old
])

#
# --- alsa.m4 ---
#
dnl Configure Paths for Alsa
dnl Some modifications by Richard Boulton <richard-alsa@tartarus.org>
dnl Christopher Lansdown <lansdoct@cs.alfred.edu>
dnl Jaroslav Kysela <perex@suse.cz>
dnl Last modification: alsa.m4,v 1.22 2002/05/27 11:14:20 tiwai Exp
dnl AM_PATH_ALSA([MINIMUM-VERSION [, ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]]])
dnl Test for libasound, and define ALSA_CFLAGS and ALSA_LIBS as appropriate.
dnl enables arguments --with-alsa-prefix=
dnl --with-alsa-enc-prefix=
dnl --disable-alsatest (this has no effect, as yet)
dnl
dnl For backwards compatibility, if ACTION_IF_NOT_FOUND is not specified,
dnl and the alsa libraries are not found, a fatal AC_MSG_ERROR() will result.
dnl
AC_DEFUN(AM_PATH_ALSA,
[dnl Save the original CFLAGS, LDFLAGS, and LIBS
alsa_save_CFLAGS="$CFLAGS"
alsa_save_LDFLAGS="$LDFLAGS"
alsa_save_LIBS="$LIBS"
alsa_found=yes
dnl
dnl Get the cflags and libraries for alsa
dnl
AC_ARG_WITH(alsa-prefix,
[ --with-alsa-prefix=PFX Prefix where Alsa library is installed(optional)],
[alsa_prefix="$withval"], [alsa_prefix=""])
AC_ARG_WITH(alsa-inc-prefix,
[ --with-alsa-inc-prefix=PFX Prefix where include libraries are (optional)],
[alsa_inc_prefix="$withval"], [alsa_inc_prefix=""])
dnl FIXME: this is not yet implemented
AC_ARG_ENABLE(alsatest,
[ --disable-alsatest Do not try to compile and run a test Alsa program],
[enable_alsatest=no],
[enable_alsatest=yes])
dnl Add any special include directories
AC_MSG_CHECKING(for ALSA CFLAGS)
if test "$alsa_inc_prefix" != "" ; then
ALSA_CFLAGS="$ALSA_CFLAGS -I$alsa_inc_prefix"
CFLAGS="$CFLAGS -I$alsa_inc_prefix"
fi
AC_MSG_RESULT($ALSA_CFLAGS)
dnl add any special lib dirs
AC_MSG_CHECKING(for ALSA LDFLAGS)
if test "$alsa_prefix" != "" ; then
ALSA_LIBS="$ALSA_LIBS -L$alsa_prefix"
LDFLAGS="$LDFLAGS $ALSA_LIBS"
fi
dnl add the alsa library
ALSA_LIBS="$ALSA_LIBS -lasound -lm -ldl -lpthread"
LIBS=`echo $LIBS | sed 's/-lm//'`
LIBS=`echo $LIBS | sed 's/-ldl//'`
LIBS=`echo $LIBS | sed 's/-lpthread//'`
LIBS=`echo $LIBS | sed 's/ //'`
LIBS="$ALSA_LIBS $LIBS"
AC_MSG_RESULT($ALSA_LIBS)
dnl Check for a working version of libasound that is of the right version.
min_alsa_version=ifelse([$1], ,0.1.1,$1)
AC_MSG_CHECKING(for libasound headers version >= $min_alsa_version)
no_alsa=""
alsa_min_major_version=`echo $min_alsa_version | \
sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\1/'`
alsa_min_minor_version=`echo $min_alsa_version | \
sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\2/'`
alsa_min_micro_version=`echo $min_alsa_version | \
sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\3/'`
AC_LANG_SAVE
AC_LANG_C
AC_TRY_COMPILE([
#include <alsa/asoundlib.h>
], [
/* ensure backward compatibility */
#if !defined(SND_LIB_MAJOR) && defined(SOUNDLIB_VERSION_MAJOR)
#define SND_LIB_MAJOR SOUNDLIB_VERSION_MAJOR
#endif
#if !defined(SND_LIB_MINOR) && defined(SOUNDLIB_VERSION_MINOR)
#define SND_LIB_MINOR SOUNDLIB_VERSION_MINOR
#endif
#if !defined(SND_LIB_SUBMINOR) && defined(SOUNDLIB_VERSION_SUBMINOR)
#define SND_LIB_SUBMINOR SOUNDLIB_VERSION_SUBMINOR
#endif
# if(SND_LIB_MAJOR > $alsa_min_major_version)
exit(0);
# else
# if(SND_LIB_MAJOR < $alsa_min_major_version)
# error not present
# endif
# if(SND_LIB_MINOR > $alsa_min_minor_version)
exit(0);
# else
# if(SND_LIB_MINOR < $alsa_min_minor_version)
# error not present
# endif
# if(SND_LIB_SUBMINOR < $alsa_min_micro_version)
# error not present
# endif
# endif
# endif
exit(0);
],
[AC_MSG_RESULT(found.)],
[AC_MSG_RESULT(not present.)
ifelse([$3], , [AC_MSG_ERROR(Sufficiently new version of libasound not found.)])
alsa_found=no]
)
AC_LANG_RESTORE
dnl Now that we know that we have the right version, let's see if we have the library and not just the headers.
AC_CHECK_LIB([asound], [snd_ctl_open],,
[ifelse([$3], , [AC_MSG_ERROR(No linkable libasound was found.)])
alsa_found=no]
)
CFLAGS="$alsa_save_CFLAGS"
LDFLAGS="$alsa_save_LDFLAGS"
LIBS="$alsa_save_LIBS"
if test "x$alsa_found" = "xyes" ; then
ifelse([$2], , :, [$2])
else
ifelse([$3], , :, [$3])
CFLAGS="$alsa_save_CFLAGS"
LDFLAGS="$alsa_save_LDFLAGS"
LIBS="$alsa_save_LIBS"
ALSA_CFLAGS=""
ALSA_LIBS=""
fi
dnl That should be it. Now just export out symbols:
AC_SUBST(ALSA_CFLAGS)
AC_SUBST(ALSA_LIBS)
])



#
# --- esd.m4 ---
#
Expand Down
48 changes: 31 additions & 17 deletions configure.in
View file
Expand Up @@ -282,39 +282,53 @@ CheckALSA()
[ --enable-alsa support the ALSA audio API [default=yes]],
, enable_alsa=yes)
if test x$enable_audio = xyes -a x$enable_alsa = xyes; then
AC_MSG_CHECKING(for ALSA audio support)
have_alsa=no
AC_TRY_COMPILE([
#include <alsa/asoundlib.h>
],[
#if SND_LIB_VERSION < ((0<<16)|(9<<8)|0)
#error Your version of ALSA is too old
#endif
snd_pcm_t *pcm_handle;
],[
AC_CHECK_LIB(asound, snd_pcm_open, have_alsa=yes)
])
AM_PATH_ALSA(0.9.0, have_alsa=yes)
if test x$have_alsa = xyes; then
AC_ARG_ENABLE(alsa-shared,
[ --enable-alsa-shared dynamically load ALSA audio support [default=yes]],
, enable_alsa_shared=yes)
alsa_lib=`ls /usr/lib/libasound.so.* | sed 's/.*\/\(.*\)/\1/; q'`
if test "x`echo $ALSA_LIBS | grep -- -L`" = "x"; then
if test "x`ls /usr/lib/libasound.so.* 2> /dev/null`" != "x"; then
ALSA_LIBS="-L/usr/lib $ALSA_LIBS"
else if test "x`ls /usr/local/lib/libasound.so.* 2> /dev/null`" != "x"; then
ALSA_LIBS="-L/usr/local/lib $ALSA_LIBS"
fi; fi
fi
alsa_lib_spec=`echo $ALSA_LIBS | sed 's/.*-L\([[^ ]]*\).*/\1\/libasound.so.*/'`
alsa_lib=`ls $alsa_lib_spec | sed 's/.*\/\(.*\)/\1/; q'`
echo "-- $alsa_lib_spec -> $alsa_lib"

if test x$use_dlopen != xyes && \
test x$enable_alsa_shared = xyes; then
AC_MSG_ERROR([You must have dlopen() support and use the --enable-dlopen option])
fi
if test x$use_dlopen = xyes && \
test x$enable_alsa_shared = xyes && test x$alsa_lib != x; then
CFLAGS="$CFLAGS -DALSA_SUPPORT -DALSA_DYNAMIC=\$(alsa_lib)"
CFLAGS="$CFLAGS -DALSA_SUPPORT -DALSA_DYNAMIC=\$(alsa_lib) $ALSA_CFLAGS"
AC_SUBST(alsa_lib)

AC_MSG_CHECKING(for dlvsym)
use_dlvsym=no
AC_TRY_COMPILE([
#include <stdio.h>
#define __USE_GNU
#include <dlfcn.h>
],[
dlvsym(NULL,"","");
],[
use_dlvsym=yes
])
AC_MSG_RESULT($use_dlvsym);
if test x$use_dlvsym = xyes; then
CFLAGS="$CFLAGS -DUSE_DLVSYM"
fi
else
CFLAGS="$CFLAGS -DALSA_SUPPORT"
SYSTEM_LIBS="$SYSTEM_LIBS -lasound"
CFLAGS="$CFLAGS -DALSA_SUPPORT $ALSA_CFLAGS"
SYSTEM_LIBS="$SYSTEM_LIBS $ALSA_LIBS"
fi
AUDIO_SUBDIRS="$AUDIO_SUBDIRS alsa"
AUDIO_DRIVERS="$AUDIO_DRIVERS alsa/libaudio_alsa.la"
else
AC_MSG_RESULT($have_alsa)
fi
fi
}
Expand Down
6 changes: 6 additions & 0 deletions src/audio/alsa/SDL_alsa_audio.c
View file
Expand Up @@ -42,7 +42,9 @@
#include "SDL_alsa_audio.h"

#ifdef ALSA_DYNAMIC
#ifdef USE_DLVSYM
#define __USE_GNU
#endif
#include <dlfcn.h>
#include "SDL_name.h"
#include "SDL_loadso.h"
Expand Down Expand Up @@ -134,7 +136,11 @@ static int LoadALSALibrary(void) {
retval = 0;
for (i = 0; i < SDL_TABLESIZE(alsa_functions); i++) {
/* *alsa_functions[i].func = SDL_LoadFunction(alsa_handle,alsa_functions[i].name);*/
#ifdef USE_DLVSYM
*alsa_functions[i].func = dlvsym(alsa_handle,alsa_functions[i].name,"ALSA_0.9");
if (!*alsa_functions[i].func)
#endif
*alsa_functions[i].func = dlsym(alsa_handle,alsa_functions[i].name);
if (!*alsa_functions[i].func) {
retval = -1;
UnloadALSALibrary();
Expand Down

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