# $Id: mutex.ac,v 11.42 2003/06/16 14:54:39 bostic Exp $

# POSIX pthreads tests: inter-process safe and intra-process only.
#
# We need to run a test here, because the PTHREAD_PROCESS_SHARED flag compiles
# fine on problematic systems, but won't actually work.  This is a problem for
# cross-compilation environments.  I think inter-process mutexes are as likely
# to fail in cross-compilation environments as real ones (especially since the
# likely cross-compilation environment is Linux, where inter-process mutexes
# don't currently work -- the latest estimate I've heard is Q1 2002, as part
# of IBM's NGPT package).  So:
#
# If checking for inter-process pthreads mutexes:
#	If it's local, run a test.
#	If it's a cross-compilation, fail.
#
# If the user specified pthreads mutexes and we're checking for intra-process
# mutexes only:
#	If it's local, run a test.
#	If it's a cross-compilation, run a link-test.
#
# So, the thing you can't do here is configure for inter-process POSIX pthread
# mutexes when cross-compiling.  Since we're using the GNU/Cygnus toolchain for
# cross-compilation, the target system is likely Linux or *BSD, so we're doing
# the right thing.
AC_DEFUN(AM_PTHREADS_SHARED, [
AC_TRY_RUN([
#include <pthread.h>
main() {
	pthread_cond_t cond;
	pthread_mutex_t mutex;
	pthread_condattr_t condattr;
	pthread_mutexattr_t mutexattr;
	exit (
	pthread_condattr_init(&condattr) ||
	pthread_condattr_setpshared(&condattr, PTHREAD_PROCESS_SHARED) ||
	pthread_mutexattr_init(&mutexattr) ||
	pthread_mutexattr_setpshared(&mutexattr, PTHREAD_PROCESS_SHARED) ||
	pthread_cond_init(&cond, &condattr) ||
	pthread_mutex_init(&mutex, &mutexattr) ||
	pthread_mutex_lock(&mutex) ||
	pthread_mutex_unlock(&mutex) ||
	pthread_mutex_destroy(&mutex) ||
	pthread_cond_destroy(&cond) ||
	pthread_condattr_destroy(&condattr) ||
	pthread_mutexattr_destroy(&mutexattr));
}], [db_cv_mutex="$1"],, [db_cv_mutex="no"])])
AC_DEFUN(AM_PTHREADS_PRIVATE, [
AC_TRY_RUN([
#include <pthread.h>
main() {
	pthread_cond_t cond;
	pthread_mutex_t mutex;
	pthread_condattr_t condattr;
	pthread_mutexattr_t mutexattr;
	exit (
	pthread_condattr_init(&condattr) ||
	pthread_mutexattr_init(&mutexattr) ||
	pthread_cond_init(&cond, &condattr) ||
	pthread_mutex_init(&mutex, &mutexattr) ||
	pthread_mutex_lock(&mutex) ||
	pthread_mutex_unlock(&mutex) ||
	pthread_mutex_destroy(&mutex) ||
	pthread_cond_destroy(&cond) ||
	pthread_condattr_destroy(&condattr) ||
	pthread_mutexattr_destroy(&mutexattr));
}], [db_cv_mutex="$1"],,
AC_TRY_LINK([
#include <pthread.h>],[
	pthread_cond_t cond;
	pthread_mutex_t mutex;
	pthread_condattr_t condattr;
	pthread_mutexattr_t mutexattr;
	exit (
	pthread_condattr_init(&condattr) ||
	pthread_mutexattr_init(&mutexattr) ||
	pthread_cond_init(&cond, &condattr) ||
	pthread_mutex_init(&mutex, &mutexattr) ||
	pthread_mutex_lock(&mutex) ||
	pthread_mutex_unlock(&mutex) ||
	pthread_mutex_destroy(&mutex) ||
	pthread_cond_destroy(&cond) ||
	pthread_condattr_destroy(&condattr) ||
	pthread_mutexattr_destroy(&mutexattr));
], [db_cv_mutex="$1"]))])

# Figure out mutexes for this compiler/architecture.
AC_DEFUN(AM_DEFINE_MUTEXES, [

# Mutexes we don't test for, but want the #defines to exist for
# other ports.
AH_TEMPLATE(HAVE_MUTEX_VMS, [Define to 1 to use VMS mutexes.])
AH_TEMPLATE(HAVE_MUTEX_VXWORKS, [Define to 1 to use VxWorks mutexes.])

AC_CACHE_CHECK([for mutexes], db_cv_mutex, [
db_cv_mutex=no

orig_libs=$LIBS

# User-specified POSIX or UI mutexes.
#
# There are two different reasons to specify mutexes: First, the application
# is already using one type of mutex and doesn't want to mix-and-match (for
# example, on Solaris, which has POSIX, UI and LWP mutexes).  Second, the
# applications POSIX pthreads mutexes don't support inter-process locking,
# but the application wants to use them anyway (for example, current Linux
# and *BSD systems).
#
# If we're on Solaris, we insist that -lthread or -lpthread be used.  The
# problem is the Solaris C library has UI/POSIX interface stubs, but they're
# broken, configuring them for inter-process mutexes doesn't return an error,
# but it doesn't work either.   Otherwise, we try first without the library
# and then with it: there's some information that SCO/UnixWare/OpenUNIX needs
# this. [#4950]
#
# Test for LWP threads before testing for UI/POSIX threads, we prefer them
# on Solaris.  There's a bug in SunOS 5.7 where applications get pwrite, not
# pwrite64, if they load the C library before the appropriate threads library,
# e.g., tclsh using dlopen to load the DB library.  By using LWP threads we
# avoid answering lots of user questions, not to mention the bugs.
if test "$db_cv_posixmutexes" = yes; then
	case "$host_os" in
	solaris*)
		db_cv_mutex="posix_library_only";;
	*)
		db_cv_mutex="posix_only";;
	esac
fi

if test "$db_cv_uimutexes" = yes; then
	case "$host_os" in
	solaris*)
		db_cv_mutex="ui_library_only";;
	*)
		db_cv_mutex="ui_only";;
	esac
fi

# User-specified Win32 mutexes (MinGW build)
if test "$db_cv_mingw" = "yes"; then
	db_cv_mutex=win32/gcc
fi

# LWP threads: _lwp_XXX
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <synch.h>],[
	static lwp_mutex_t mi = SHAREDMUTEX;
	static lwp_cond_t ci = SHAREDCV;
	lwp_mutex_t mutex = mi;
	lwp_cond_t cond = ci;
	exit (
	_lwp_mutex_lock(&mutex) ||
	_lwp_mutex_unlock(&mutex));
], [db_cv_mutex="Solaris/lwp"])
fi

# UI threads: thr_XXX
#
# Try with and without the -lthread library.
if test "$db_cv_mutex" = no -o "$db_cv_mutex" = "ui_only"; then
AC_TRY_LINK([
#include <thread.h>
#include <synch.h>],[
	mutex_t mutex;
	cond_t cond;
	int type = USYNC_PROCESS;
	exit (
	mutex_init(&mutex, type, NULL) ||
	cond_init(&cond, type, NULL) ||
	mutex_lock(&mutex) ||
	mutex_unlock(&mutex));
], [db_cv_mutex="UI/threads"])
fi
if test "$db_cv_mutex" = no -o \
    "$db_cv_mutex" = "ui_only" -o "$db_cv_mutex" = "ui_library_only"; then
LIBS="$LIBS -lthread"
AC_TRY_LINK([
#include <thread.h>
#include <synch.h>],[
	mutex_t mutex;
	cond_t cond;
	int type = USYNC_PROCESS;
	exit (
	mutex_init(&mutex, type, NULL) ||
	cond_init(&cond, type, NULL) ||
	mutex_lock(&mutex) ||
	mutex_unlock(&mutex));
], [db_cv_mutex="UI/threads/library"])
LIBS="$orig_libs"
fi
if test "$db_cv_mutex" = "ui_only" -o "$db_cv_mutex" = "ui_library_only"; then
	AC_MSG_ERROR([unable to find UI mutex interfaces])
fi

# POSIX.1 pthreads: pthread_XXX
#
# Try with and without the -lpthread library.  If the user specified we use
# POSIX pthreads mutexes, and we fail to find the full interface, try and
# configure for just intra-process support.
if test "$db_cv_mutex" = no -o "$db_cv_mutex" = "posix_only"; then
	AM_PTHREADS_SHARED("POSIX/pthreads")
fi
if test "$db_cv_mutex" = no -o \
    "$db_cv_mutex" = "posix_only" -o "$db_cv_mutex" = "posix_library_only"; then
	LIBS="$LIBS -lpthread"
	AM_PTHREADS_SHARED("POSIX/pthreads/library")
	LIBS="$orig_libs"
fi
if test "$db_cv_mutex" = "posix_only"; then
	AM_PTHREADS_PRIVATE("POSIX/pthreads/private")
fi
if test "$db_cv_mutex" = "posix_only" -o \
    "$db_cv_mutex" = "posix_library_only"; then
	LIBS="$LIBS -lpthread"
	AM_PTHREADS_PRIVATE("POSIX/pthreads/library/private")
	LIBS="$orig_libs"
fi

if test "$db_cv_mutex" = "posix_only" -o \
    "$db_cv_mutex" = "posix_library_only"; then
	AC_MSG_ERROR([unable to find POSIX 1003.1 mutex interfaces])
fi

# msemaphore: HPPA only
# Try HPPA before general msem test, it needs special alignment.
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <sys/mman.h>],[
#if defined(__hppa)
	typedef msemaphore tsl_t;
	msemaphore x;
	msem_init(&x, 0);
	msem_lock(&x, 0);
	msem_unlock(&x, 0);
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="HP/msem_init"])
fi

# msemaphore: AIX, OSF/1
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <sys/types.h>
#include <sys/mman.h>],[
	typedef msemaphore tsl_t;
	msemaphore x;
	msem_init(&x, 0);
	msem_lock(&x, 0);
	msem_unlock(&x, 0);
	exit(0);
], [db_cv_mutex="UNIX/msem_init"])
fi

# ReliantUNIX
if test "$db_cv_mutex" = no; then
LIBS="$LIBS -lmproc"
AC_TRY_LINK([
#include <ulocks.h>],[
	typedef spinlock_t tsl_t;
	spinlock_t x;
	initspin(&x, 1);
	cspinlock(&x);
	spinunlock(&x);
], [db_cv_mutex="ReliantUNIX/initspin"])
LIBS="$orig_libs"
fi

# SCO: UnixWare has threads in libthread, but OpenServer doesn't.
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__USLC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="SCO/x86/cc-assembly"])
fi

# abilock_t: SGI
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <abi_mutex.h>],[
	typedef abilock_t tsl_t;
	abilock_t x;
	init_lock(&x);
	acquire_lock(&x);
	release_lock(&x);
], [db_cv_mutex="SGI/init_lock"])
fi

# sema_t: Solaris
# The sema_XXX calls do not work on Solaris 5.5.  I see no reason to ever
# turn this test on, unless we find some other platform that uses the old
# POSIX.1 interfaces.  (I plan to move directly to pthreads on Solaris.)
if test "$db_cv_mutex" = DOESNT_WORK; then
AC_TRY_LINK([
#include <synch.h>],[
	typedef sema_t tsl_t;
	sema_t x;
	sema_init(&x, 1, USYNC_PROCESS, NULL);
	sema_wait(&x);
	sema_post(&x);
], [db_cv_mutex="UNIX/sema_init"])
fi

# _lock_try/_lock_clear: Solaris
# On Solaris systems without Pthread or UI mutex interfaces, DB uses the
# undocumented _lock_try _lock_clear function calls instead of either the
# sema_trywait(3T) or sema_wait(3T) function calls.  This is because of
# problems in those interfaces in some releases of the Solaris C library.
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <sys/machlock.h>],[
	typedef lock_t tsl_t;
	lock_t x;
	_lock_try(&x);
	_lock_clear(&x);
], [db_cv_mutex="Solaris/_lock_try"])
fi

# _check_lock/_clear_lock: AIX
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <sys/atomic_op.h>],[
	int x;
	_check_lock(&x,0,1);
	_clear_lock(&x,0);
], [db_cv_mutex="AIX/_check_lock"])
fi

# _spin_lock_try/_spin_unlock: Apple/Darwin
if test "$db_cv_mutex" = no; then
AC_TRY_LINK(,[
	int x;
	_spin_lock_try(&x);
	_spin_unlock(&x);
], [db_cv_mutex="Darwin/_spin_lock_try"])
fi

# Tru64/cc
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__alpha) && defined(__DECC)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="Tru64/cc-assembly"])
fi

# Alpha/gcc
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__alpha) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="ALPHA/gcc-assembly"])
fi

# ARM/gcc: Linux
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__arm__) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="ARM/gcc-assembly"])
fi

# PaRisc/gcc: HP/UX
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if (defined(__hppa) || defined(__hppa__)) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="HPPA/gcc-assembly"])
fi

# PPC/gcc:
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if (defined(__powerpc__) || defined(__ppc__)) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="PPC/gcc-assembly"])
fi

# Sparc/gcc: SunOS, Solaris
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__sparc__) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="Sparc/gcc-assembly"])
fi

# 68K/gcc: SunOS
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if (defined(mc68020) || defined(sun3)) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="68K/gcc-assembly"])
fi

# x86/gcc: FreeBSD, NetBSD, BSD/OS, Linux
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if (defined(i386) || defined(__i386__)) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="x86/gcc-assembly"])
fi

# S390/cc: IBM OS/390 Unix
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__MVS__) && defined(__IBMC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="S390/cc-assembly"])
fi

# S390/gcc: Linux
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__s390__) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="S390/gcc-assembly"])
fi

# ia86/gcc: Linux
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__ia64) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="ia64/gcc-assembly"])
fi

# uts/cc: UTS
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(_UTS)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex="UTS/cc-assembly"])
fi

# default to UNIX fcntl system call mutexes.
if test "$db_cv_mutex" = no; then
	db_cv_mutex="UNIX/fcntl"
fi
])

case "$db_cv_mutex" in
68K/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_68K_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_68K_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and 68K assembly language mutexes.]);;
AIX/_check_lock)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_AIX_CHECK_LOCK)
			AH_TEMPLATE(HAVE_MUTEX_AIX_CHECK_LOCK,
			    [Define to 1 to use the AIX _check_lock mutexes.]);;
Darwin/_spin_lock_try)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_DARWIN_SPIN_LOCK_TRY)
			AH_TEMPLATE(HAVE_MUTEX_DARWIN_SPIN_LOCK_TRY,
			    [Define to 1 to use the Apple/Darwin _spin_lock_try mutexes.]);;
ALPHA/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_ALPHA_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_ALPHA_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and Alpha assembly language mutexes.]);;
ARM/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_ARM_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_ARM_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and ARM assembly language mutexes.]);;
HP/msem_init)		ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_HPPA_MSEM_INIT)
			AH_TEMPLATE(HAVE_MUTEX_HPPA_MSEM_INIT,
			    [Define to 1 to use the msem_XXX mutexes on HP-UX.]);;
HPPA/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_HPPA_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_HPPA_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and PaRisc assembly language mutexes.]);;
ia64/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_IA64_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_IA64_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and IA64 assembly language mutexes.]);;
POSIX/pthreads)		ADDITIONAL_OBJS="mut_pthread${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_PTHREADS)
			AH_TEMPLATE(HAVE_MUTEX_PTHREADS,
			    [Define to 1 to use POSIX 1003.1 pthread_XXX mutexes.]);;
POSIX/pthreads/private)	ADDITIONAL_OBJS="mut_pthread${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_PTHREADS)
			AH_TEMPLATE(HAVE_MUTEX_PTHREADS,
			    [Define to 1 to use POSIX 1003.1 pthread_XXX mutexes.])
			AC_DEFINE(HAVE_MUTEX_THREAD_ONLY)
			AH_TEMPLATE(HAVE_MUTEX_THREAD_ONLY,
			    [Define to 1 to configure mutexes intra-process only.]);;
POSIX/pthreads/library)	LIBS="$LIBS -lpthread"
			ADDITIONAL_OBJS="mut_pthread${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_PTHREADS)
			AH_TEMPLATE(HAVE_MUTEX_PTHREADS,
			    [Define to 1 to use POSIX 1003.1 pthread_XXX mutexes.]);;
POSIX/pthreads/library/private)
			LIBS="$LIBS -lpthread"
			ADDITIONAL_OBJS="mut_pthread${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_PTHREADS)
			AH_TEMPLATE(HAVE_MUTEX_PTHREADS,
			    [Define to 1 to use POSIX 1003.1 pthread_XXX mutexes.])
			AC_DEFINE(HAVE_MUTEX_THREAD_ONLY)
			AH_TEMPLATE(HAVE_MUTEX_THREAD_ONLY,
			    [Define to 1 to configure mutexes intra-process only.]);;
PPC/gcc-assembly)
			ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_PPC_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_PPC_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and PowerPC assembly language mutexes.]);;
ReliantUNIX/initspin)	LIBS="$LIBS -lmproc"
			ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_RELIANTUNIX_INITSPIN)
			AH_TEMPLATE(HAVE_MUTEX_RELIANTUNIX_INITSPIN,
			    [Define to 1 to use Reliant UNIX initspin mutexes.]);;
S390/cc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_S390_CC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_S390_CC_ASSEMBLY,
			    [Define to 1 to use the IBM C compiler and S/390 assembly language mutexes.]);;
S390/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_S390_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_S390_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and S/390 assembly language mutexes.]);;
SCO/x86/cc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_SCO_X86_CC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_SCO_X86_CC_ASSEMBLY,
			    [Define to 1 to use the SCO compiler and x86 assembly language mutexes.]);;
SGI/init_lock)		ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_SGI_INIT_LOCK)
			AH_TEMPLATE(HAVE_MUTEX_SGI_INIT_LOCK,
			    [Define to 1 to use the SGI XXX_lock mutexes.]);;
Solaris/_lock_try)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_SOLARIS_LOCK_TRY)
			AH_TEMPLATE(HAVE_MUTEX_SOLARIS_LOCK_TRY,
			    [Define to 1 to use the Solaris _lock_XXX mutexes.]);;
Solaris/lwp)		ADDITIONAL_OBJS="mut_pthread${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_SOLARIS_LWP)
			AH_TEMPLATE(HAVE_MUTEX_SOLARIS_LWP,
			    [Define to 1 to use the Solaris lwp threads mutexes.]);;
Sparc/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_SPARC_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_SPARC_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and Sparc assembly language mutexes.]);;
Tru64/cc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_TRU64_CC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_TRU64_CC_ASSEMBLY,
			    [Define to 1 to use the CC compiler and Tru64 assembly language mutexes.]);;

UI/threads)		ADDITIONAL_OBJS="mut_pthread${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_UI_THREADS)
			AH_TEMPLATE(HAVE_MUTEX_UI_THREADS,
			    [Define to 1 to use the UNIX International mutexes.]);;
UI/threads/library)	LIBS="$LIBS -lthread"
			ADDITIONAL_OBJS="mut_pthread${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_UI_THREADS)
			AH_TEMPLATE(HAVE_MUTEX_UI_THREADS,
			    [Define to 1 to use the UNIX International mutexes.]);;
UNIX/msem_init)		ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_MSEM_INIT)
			AH_TEMPLATE(HAVE_MUTEX_MSEM_INIT,
			    [Define to 1 to use the msem_XXX mutexes on systems other than HP-UX.]);;
UNIX/sema_init)		ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_SEMA_INIT)
			AH_TEMPLATE(HAVE_MUTEX_SEMA_INIT,
			    [Define to 1 to use the obsolete POSIX 1003.1 sema_XXX mutexes.]);;
UTS/cc-assembly)	ADDITIONAL_OBJS="uts4.cc${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_UTS_CC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_UTS_CC_ASSEMBLY,
			    [Define to 1 to use the UTS compiler and assembly language mutexes.]);;
win32)			ADDITIONAL_OBJS="mut_win32${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_WIN32)
			AH_TEMPLATE(HAVE_MUTEX_WIN32, [Define to 1 to use the MSVC compiler and Windows mutexes.]);;
win32/gcc)		ADDITIONAL_OBJS="mut_win32${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_WIN32_GCC)
			AH_TEMPLATE(HAVE_MUTEX_WIN32_GCC, [Define to 1 to use the GCC compiler and Windows mutexes.]);;
x86/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_X86_GCC_ASSEMBLY)
			AH_TEMPLATE(HAVE_MUTEX_X86_GCC_ASSEMBLY,
			    [Define to 1 to use the GCC compiler and x86 assembly language mutexes.]);;
UNIX/fcntl)		AC_MSG_WARN(
			    [NO FAST MUTEXES FOUND FOR THIS COMPILER/ARCHITECTURE.])
			ADDITIONAL_OBJS="mut_fcntl${o} $ADDITIONAL_OBJS"
			AC_DEFINE(HAVE_MUTEX_FCNTL)
			AH_TEMPLATE(HAVE_MUTEX_FCNTL,
			    [Define to 1 to use the UNIX fcntl system call mutexes.]);;
*)			AC_MSG_ERROR([Unknown mutex interface: $db_cv_mutex]);;
esac

if test "$db_cv_mutex" != "UNIX/fcntl"; then
	AC_DEFINE(HAVE_MUTEX_THREADS)
	AH_TEMPLATE(HAVE_MUTEX_THREADS,
	    [Define to 1 if fast mutexes are available.])
fi

# There are 3 classes of mutexes:
#
# 1: Mutexes requiring no cleanup, for example, test-and-set mutexes.
# 2: Mutexes that must be destroyed, but which don't hold permanent system
#    resources, for example, pthread mutexes on MVS aka OS/390 aka z/OS.
# 3: Mutexes that must be destroyed, even after the process is gone, for
#    example, pthread mutexes on QNX and binary semaphores on VxWorks.
#
# DB cannot currently distinguish between #2 and #3 because DB does not know
# if the application is running environment recovery as part of startup and
# does not need to do cleanup, or if the environment is being removed and/or
# recovered in a loop in the application, and so does need to clean up.  If
# we get it wrong, we're going to call the mutex destroy routine on a random
# piece of memory, which usually works, but just might drop core.  For now,
# we group #2 and #3 into the HAVE_MUTEX_SYSTEM_RESOURCES define, until we
# have a better solution or reason to solve this in a general way -- so far,
# the places we've needed to handle this are few.
AH_TEMPLATE(HAVE_MUTEX_SYSTEM_RESOURCES,
    [Define to 1 if mutexes hold system resources.])

case "$host_os$db_cv_mutex" in
*qnx*POSIX/pthread*|openedition*POSIX/pthread*)
	AC_DEFINE(HAVE_MUTEX_SYSTEM_RESOURCES);;
esac])
