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| -rw-r--r-- | m4/threadlib.m4 | 669 |
1 files changed, 669 insertions, 0 deletions
diff --git a/m4/threadlib.m4 b/m4/threadlib.m4 new file mode 100644 index 0000000..7202b95 --- /dev/null +++ b/m4/threadlib.m4 @@ -0,0 +1,669 @@ +# threadlib.m4 serial 35 +dnl Copyright (C) 2005-2023 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +dnl From Bruno Haible. + +AC_PREREQ([2.60]) + +dnl The general structure of the multithreading modules in gnulib is that we +dnl have three set of modules: +dnl +dnl * POSIX API: +dnl pthread, which combines +dnl pthread-h +dnl pthread-thread +dnl pthread-once +dnl pthread-mutex +dnl pthread-rwlock +dnl pthread-cond +dnl pthread-tss +dnl pthread-spin +dnl sched_yield +dnl +dnl * ISO C API: +dnl threads, which combines +dnl threads-h +dnl thrd +dnl mtx +dnl cnd +dnl tss +dnl +dnl * Gnulib API, with an implementation that can be chosen at configure +dnl time through the option --enable-threads=... +dnl thread +dnl lock +dnl cond +dnl tls +dnl yield +dnl +dnl They are independent, except for the fact that +dnl - the implementation of the ISO C API may use the POSIX (or some other +dnl platform dependent) API, +dnl - the implementation of the Gnulib API may use the POSIX or ISO C or +dnl some other platform dependent API, depending on the --enable-threads +dnl option. +dnl +dnl This file contains macros for all of these APIs! + +dnl ============================================================================ +dnl Macros for all thread APIs + +AC_DEFUN([gl_ANYTHREADLIB_EARLY], +[ + AC_REQUIRE([AC_CANONICAL_HOST]) + if test -z "$gl_anythreadlib_early_done"; then + case "$host_os" in + osf*) + # On OSF/1, the compiler needs the flag -D_REENTRANT so that it + # groks <pthread.h>. cc also understands the flag -pthread, but + # we don't use it because 1. gcc-2.95 doesn't understand -pthread, + # 2. putting a flag into CPPFLAGS that has an effect on the linker + # causes the AC_LINK_IFELSE test below to succeed unexpectedly, + # leading to wrong values of LIBTHREAD and LTLIBTHREAD. + CPPFLAGS="$CPPFLAGS -D_REENTRANT" + ;; + esac + # Some systems optimize for single-threaded programs by default, and + # need special flags to disable these optimizations. For example, the + # definition of 'errno' in <errno.h>. + case "$host_os" in + aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;; + solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;; + esac + gl_anythreadlib_early_done=done + fi +]) + +dnl Checks whether the compiler and linker support weak declarations of symbols. + +AC_DEFUN([gl_WEAK_SYMBOLS], +[ + AC_REQUIRE([AC_CANONICAL_HOST]) + AC_CACHE_CHECK([whether imported symbols can be declared weak], + [gl_cv_have_weak], + [case "$host_os" in + cygwin*) + dnl On Cygwin 3.2.0 with gcc 10.2, the test below would succeed, but + dnl programs that use pthread_in_use() with weak symbol references + dnl crash miserably at runtime. + gl_cv_have_weak="guessing no" + ;; + *) + gl_cv_have_weak=no + dnl First, test whether the compiler accepts it syntactically. + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[extern void xyzzy (); +#pragma weak xyzzy]], + [[xyzzy();]])], + [gl_cv_have_weak=maybe]) + if test $gl_cv_have_weak = maybe; then + dnl Second, test whether it actually works. On Cygwin 1.7.2, with + dnl gcc 4.3, symbols declared weak always evaluate to the address 0. + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#include <stdio.h> +#pragma weak fputs +int main () +{ + return (fputs == NULL); +}]])], + [gl_cv_have_weak=yes], + [gl_cv_have_weak=no], + [dnl When cross-compiling, assume that only ELF platforms support + dnl weak symbols. + AC_EGREP_CPP([Extensible Linking Format], + [#ifdef __ELF__ + Extensible Linking Format + #endif + ], + [gl_cv_have_weak="guessing yes"], + [gl_cv_have_weak="guessing no"]) + ]) + fi + ;; + esac + dnl But when linking statically, weak symbols don't work. + case " $LDFLAGS " in + *" -static "*) gl_cv_have_weak=no ;; + esac + dnl Test for a bug in FreeBSD 11: A link error occurs when using a weak + dnl symbol and linking against a shared library that has a dependency on + dnl the shared library that defines the symbol. + case "$gl_cv_have_weak" in + *yes) + case "$host_os" in + freebsd* | dragonfly* | midnightbsd*) + : > conftest1.c + $CC $CPPFLAGS $CFLAGS $LDFLAGS -fPIC -shared -o libempty.so conftest1.c -lpthread >&AS_MESSAGE_LOG_FD 2>&1 + cat <<EOF > conftest2.c +#include <pthread.h> +#pragma weak pthread_mutexattr_gettype +int main () +{ + return (pthread_mutexattr_gettype != NULL); +} +EOF + $CC $CPPFLAGS $CFLAGS $LDFLAGS -o conftest conftest2.c libempty.so >&AS_MESSAGE_LOG_FD 2>&1 \ + || gl_cv_have_weak=no + rm -f conftest1.c libempty.so conftest2.c conftest + ;; + esac + ;; + esac + ]) + case "$gl_cv_have_weak" in + *yes) + AC_DEFINE([HAVE_WEAK_SYMBOLS], [1], + [Define to 1 if the compiler and linker support weak declarations of symbols.]) + ;; + esac +]) + +dnl ============================================================================ +dnl Macros for the POSIX API + +dnl gl_PTHREADLIB +dnl ------------- +dnl Tests for the libraries needs for using the POSIX threads API. +dnl Sets the variable LIBPTHREAD to the linker options for use in a Makefile. +dnl Sets the variable LIBPMULTITHREAD, for programs that really need +dnl multithread functionality. The difference between LIBPTHREAD and +dnl LIBPMULTITHREAD is that on platforms supporting weak symbols, typically +dnl LIBPTHREAD is empty whereas LIBPMULTITHREAD is not. +dnl Sets the variable SCHED_YIELD_LIB to the linker options needed to use the +dnl sched_yield() function. +dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for +dnl multithread-safe programs. +dnl Defines the C macro HAVE_PTHREAD_API if (at least parts of) the POSIX +dnl threads API is available. + +dnl The guts of gl_PTHREADLIB. Needs to be expanded only once. + +AC_DEFUN([gl_PTHREADLIB_BODY], +[ + AC_REQUIRE([gl_ANYTHREADLIB_EARLY]) + if test -z "$gl_pthreadlib_body_done"; then + gl_pthread_api=no + LIBPTHREAD= + LIBPMULTITHREAD= + # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that + # it groks <pthread.h>. It's added above, in gl_ANYTHREADLIB_EARLY. + AC_CHECK_HEADER([pthread.h], + [gl_have_pthread_h=yes], [gl_have_pthread_h=no]) + if test "$gl_have_pthread_h" = yes; then + # Other possible tests: + # -lpthreads (FSU threads, PCthreads) + # -lgthreads + # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist + # in libc. IRIX 6.5 has the first one in both libc and libpthread, but + # the second one only in libpthread, and lock.c needs it. + # + # If -pthread works, prefer it to -lpthread, since Ubuntu 14.04 + # needs -pthread for some reason. See: + # https://lists.gnu.org/r/bug-gnulib/2014-09/msg00023.html + save_LIBS=$LIBS + for gl_pthread in '' '-pthread'; do + LIBS="$LIBS $gl_pthread" + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#include <pthread.h> + pthread_mutex_t m; + pthread_mutexattr_t ma; + ]], + [[pthread_mutex_lock (&m); + pthread_mutexattr_init (&ma);]])], + [gl_pthread_api=yes + LIBPTHREAD=$gl_pthread + LIBPMULTITHREAD=$gl_pthread]) + LIBS=$save_LIBS + test $gl_pthread_api = yes && break + done + echo "$as_me:__oline__: gl_pthread_api=$gl_pthread_api" >&AS_MESSAGE_LOG_FD + echo "$as_me:__oline__: LIBPTHREAD=$LIBPTHREAD" >&AS_MESSAGE_LOG_FD + + gl_pthread_in_glibc=no + # On Linux with glibc >= 2.34, libc contains the fully functional + # pthread functions. + case "$host_os" in + linux*) + AC_EGREP_CPP([Lucky user], + [#include <features.h> + #ifdef __GNU_LIBRARY__ + #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 34) || (__GLIBC__ > 2) + Lucky user + #endif + #endif + ], + [gl_pthread_in_glibc=yes], + []) + ;; + esac + echo "$as_me:__oline__: gl_pthread_in_glibc=$gl_pthread_in_glibc" >&AS_MESSAGE_LOG_FD + + # Test for libpthread by looking for pthread_kill. (Not pthread_self, + # since it is defined as a macro on OSF/1.) + if test $gl_pthread_api = yes && test -z "$LIBPTHREAD"; then + # The program links fine without libpthread. But it may actually + # need to link with libpthread in order to create multiple threads. + AC_CHECK_LIB([pthread], [pthread_kill], + [if test $gl_pthread_in_glibc = yes; then + LIBPMULTITHREAD= + else + LIBPMULTITHREAD=-lpthread + # On Solaris and HP-UX, most pthread functions exist also in libc. + # Therefore pthread_in_use() needs to actually try to create a + # thread: pthread_create from libc will fail, whereas + # pthread_create will actually create a thread. + # On Solaris 10 or newer, this test is no longer needed, because + # libc contains the fully functional pthread functions. + case "$host_os" in +changequote(,)dnl + solaris | solaris2.[1-9] | solaris2.[1-9].* | hpux*) +changequote([,])dnl + AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1], + [Define if the pthread_in_use() detection is hard.]) + esac + fi + ]) + elif test $gl_pthread_api != yes; then + # Some library is needed. Try libpthread and libc_r. + AC_CHECK_LIB([pthread], [pthread_kill], + [gl_pthread_api=yes + LIBPTHREAD=-lpthread + LIBPMULTITHREAD=-lpthread]) + if test $gl_pthread_api != yes; then + # For FreeBSD 4. + AC_CHECK_LIB([c_r], [pthread_kill], + [gl_pthread_api=yes + LIBPTHREAD=-lc_r + LIBPMULTITHREAD=-lc_r]) + fi + fi + echo "$as_me:__oline__: LIBPMULTITHREAD=$LIBPMULTITHREAD" >&AS_MESSAGE_LOG_FD + fi + AC_MSG_CHECKING([whether POSIX threads API is available]) + AC_MSG_RESULT([$gl_pthread_api]) + AC_SUBST([LIBPTHREAD]) + AC_SUBST([LIBPMULTITHREAD]) + if test $gl_pthread_api = yes; then + AC_DEFINE([HAVE_PTHREAD_API], [1], + [Define if you have the <pthread.h> header and the POSIX threads API.]) + fi + + dnl On some systems, sched_yield is in librt, rather than in libpthread. + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#include <sched.h>]], + [[sched_yield ();]])], + [SCHED_YIELD_LIB= + ], + [dnl Solaris 7...10 has sched_yield in librt, not in libpthread or libc. + AC_CHECK_LIB([rt], [sched_yield], [SCHED_YIELD_LIB=-lrt], + [dnl Solaris 2.5.1, 2.6 has sched_yield in libposix4, not librt. + AC_CHECK_LIB([posix4], [sched_yield], [SCHED_YIELD_LIB=-lposix4])]) + ]) + AC_SUBST([SCHED_YIELD_LIB]) + dnl For backward compatibility. + LIB_SCHED_YIELD="$SCHED_YIELD_LIB" + AC_SUBST([LIB_SCHED_YIELD]) + + gl_pthreadlib_body_done=done + fi +]) + +AC_DEFUN([gl_PTHREADLIB], +[ + AC_REQUIRE([gl_ANYTHREADLIB_EARLY]) + gl_PTHREADLIB_BODY +]) + +dnl ============================================================================ +dnl Macros for the ISO C API + +dnl gl_STDTHREADLIB +dnl --------------- +dnl Tests for the libraries needs for using the ISO C threads API. +dnl Sets the variable LIBSTDTHREAD to the linker options for use in a Makefile. +dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for +dnl multithread-safe programs. +dnl Defines the C macro HAVE_THREADS_H if (at least parts of) the ISO C threads +dnl API is available. + +dnl The guts of gl_STDTHREADLIB. Needs to be expanded only once. + +AC_DEFUN([gl_STDTHREADLIB_BODY], +[ + AC_REQUIRE([gl_ANYTHREADLIB_EARLY]) + AC_REQUIRE([AC_CANONICAL_HOST]) + if test -z "$gl_stdthreadlib_body_done"; then + AC_CHECK_HEADERS_ONCE([threads.h]) + + case "$host_os" in + mingw*) + LIBSTDTHREAD= + ;; + *) + gl_PTHREADLIB_BODY + if test $ac_cv_header_threads_h = yes; then + dnl glibc >= 2.29 has thrd_create in libpthread. + dnl FreeBSD >= 10 has thrd_create in libstdthreads; this library depends + dnl on libpthread (for the symbol 'pthread_mutexattr_gettype'). + dnl glibc >= 2.34, AIX >= 7.1, and Solaris >= 11.4 have thrd_create in + dnl libc. + gl_CHECK_FUNCS_ANDROID([thrd_create], [[#include <threads.h>]]) + if test $ac_cv_func_thrd_create = yes; then + LIBSTDTHREAD= + else + AC_CHECK_LIB([stdthreads], [thrd_create], [ + LIBSTDTHREAD='-lstdthreads -lpthread' + ], [ + dnl Guess that thrd_create is in libpthread. + LIBSTDTHREAD="$LIBPMULTITHREAD" + ]) + fi + else + dnl Libraries needed by thrd.c, mtx.c, cnd.c, tss.c. + LIBSTDTHREAD="$LIBPMULTITHREAD $SCHED_YIELD_LIB" + fi + ;; + esac + AC_SUBST([LIBSTDTHREAD]) + + AC_MSG_CHECKING([whether ISO C threads API is available]) + AC_MSG_RESULT([$ac_cv_header_threads_h]) + gl_stdthreadlib_body_done=done + fi +]) + +AC_DEFUN([gl_STDTHREADLIB], +[ + AC_REQUIRE([gl_ANYTHREADLIB_EARLY]) + gl_STDTHREADLIB_BODY +]) + +dnl ============================================================================ +dnl Macros for the Gnulib API + +dnl gl_THREADLIB +dnl ------------ +dnl Tests for a multithreading library to be used. +dnl If the configure.ac contains a definition of the gl_THREADLIB_DEFAULT_NO +dnl (it must be placed before the invocation of gl_THREADLIB_EARLY!), then the +dnl default is 'no', otherwise it is system dependent. In both cases, the user +dnl can change the choice through the options --enable-threads=choice or +dnl --disable-threads. +dnl Defines at most one of the macros USE_ISOC_THREADS, USE_POSIX_THREADS, +dnl USE_ISOC_AND_POSIX_THREADS, USE_WINDOWS_THREADS. +dnl The choice --enable-threads=isoc+posix is available only on platforms that +dnl have both the ISO C and the POSIX threads APIs. It has the effect of using +dnl the ISO C API for most things and the POSIX API only for creating and +dnl controlling threads (because there is no equivalent to pthread_atfork in +dnl the ISO C API). +dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use +dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with +dnl libtool). +dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for +dnl programs that really need multithread functionality. The difference +dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak +dnl symbols, typically LIBTHREAD is empty whereas LIBMULTITHREAD is not. +dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for +dnl multithread-safe programs. +dnl Since support for GNU pth was removed, $LTLIBTHREAD and $LIBTHREAD have the +dnl same value, and similarly $LTLIBMULTITHREAD and $LIBMULTITHREAD have the +dnl same value. Only system libraries are needed. + +AC_DEFUN([gl_THREADLIB_EARLY], +[ + AC_REQUIRE([gl_THREADLIB_EARLY_BODY]) +]) + +dnl The guts of gl_THREADLIB_EARLY. Needs to be expanded only once. + +AC_DEFUN([gl_THREADLIB_EARLY_BODY], +[ + dnl Ordering constraints: This macro modifies CPPFLAGS in a way that + dnl influences the result of the autoconf tests that test for *_unlocked + dnl declarations, on AIX 5 at least. Therefore it must come early. + AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl + AC_BEFORE([$0], [gl_ARGP])dnl + + AC_REQUIRE([AC_CANONICAL_HOST]) + dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems. + AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) + dnl Check for multithreading. + m4_ifdef([gl_THREADLIB_DEFAULT_NO], + [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])], + [m4_divert_text([DEFAULTS], [gl_use_threads_default=])]) + m4_divert_text([DEFAULTS], [gl_use_winpthreads_default=]) + AC_ARG_ENABLE([threads], +AS_HELP_STRING([--enable-threads={isoc|posix|isoc+posix|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [ +AS_HELP_STRING([--disable-threads], [build without multithread safety])]), + [gl_use_threads=$enableval], + [if test -n "$gl_use_threads_default"; then + gl_use_threads="$gl_use_threads_default" + else +changequote(,)dnl + case "$host_os" in + dnl Disable multithreading by default on OSF/1, because it interferes + dnl with fork()/exec(): When msgexec is linked with -lpthread, its + dnl child process gets an endless segmentation fault inside execvp(). + osf*) gl_use_threads=no ;; + dnl Disable multithreading by default on Cygwin 1.5.x, because it has + dnl bugs that lead to endless loops or crashes. See + dnl <https://cygwin.com/ml/cygwin/2009-08/msg00283.html>. + cygwin*) + case `uname -r` in + 1.[0-5].*) gl_use_threads=no ;; + *) gl_use_threads=yes ;; + esac + ;; + dnl Obey gl_AVOID_WINPTHREAD on mingw. + mingw*) + case "$gl_use_winpthreads_default" in + yes) gl_use_threads=posix ;; + no) gl_use_threads=windows ;; + *) gl_use_threads=yes ;; + esac + ;; + *) gl_use_threads=yes ;; + esac +changequote([,])dnl + fi + ]) + if test "$gl_use_threads" = yes \ + || test "$gl_use_threads" = isoc \ + || test "$gl_use_threads" = posix \ + || test "$gl_use_threads" = isoc+posix; then + # For using <threads.h> or <pthread.h>: + gl_ANYTHREADLIB_EARLY + fi +]) + +dnl The guts of gl_THREADLIB. Needs to be expanded only once. + +AC_DEFUN([gl_THREADLIB_BODY], +[ + AC_REQUIRE([gl_THREADLIB_EARLY_BODY]) + gl_threads_api=none + LIBTHREAD= + LTLIBTHREAD= + LIBMULTITHREAD= + LTLIBMULTITHREAD= + if test "$gl_use_threads" != no; then + dnl Check whether the compiler and linker support weak declarations. + gl_WEAK_SYMBOLS + if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then + dnl If we use weak symbols to implement pthread_in_use / pth_in_use / + dnl thread_in_use, we also need to test whether the ISO C 11 thrd_create + dnl facility is in use. + AC_CHECK_HEADERS_ONCE([threads.h]) + : + fi + if test "$gl_use_threads" = isoc || test "$gl_use_threads" = isoc+posix; then + AC_CHECK_HEADERS_ONCE([threads.h]) + gl_have_isoc_threads="$ac_cv_header_threads_h" + fi + if test "$gl_use_threads" = yes \ + || test "$gl_use_threads" = posix \ + || test "$gl_use_threads" = isoc+posix; then + gl_PTHREADLIB_BODY + LIBTHREAD=$LIBPTHREAD LTLIBTHREAD=$LIBPTHREAD + LIBMULTITHREAD=$LIBPMULTITHREAD LTLIBMULTITHREAD=$LIBPMULTITHREAD + if test $gl_pthread_api = yes; then + if test "$gl_use_threads" = isoc+posix && test "$gl_have_isoc_threads" = yes; then + gl_threads_api='isoc+posix' + AC_DEFINE([USE_ISOC_AND_POSIX_THREADS], [1], + [Define if the combination of the ISO C and POSIX multithreading APIs can be used.]) + LIBTHREAD= LTLIBTHREAD= + else + gl_threads_api=posix + AC_DEFINE([USE_POSIX_THREADS], [1], + [Define if the POSIX multithreading library can be used.]) + if test -z "$LIBMULTITHREAD" && test -z "$LTLIBMULTITHREAD"; then + AC_DEFINE([USE_POSIX_THREADS_FROM_LIBC], [1], + [Define if references to the POSIX multithreading library are satisfied by libc.]) + else + if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then + AC_DEFINE([USE_POSIX_THREADS_WEAK], [1], + [Define if references to the POSIX multithreading library should be made weak.]) + LIBTHREAD= LTLIBTHREAD= + else + case "$host_os" in + freebsd* | dragonfly* | midnightbsd*) + if test "x$LIBTHREAD" != "x$LIBMULTITHREAD"; then + dnl If weak symbols can't tell whether pthread_create(), pthread_key_create() + dnl etc. will succeed, we need a runtime test. + AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1], + [Define if the pthread_in_use() detection is hard.]) + fi + ;; + esac + fi + fi + fi + fi + fi + if test $gl_threads_api = none; then + if test "$gl_use_threads" = isoc && test "$gl_have_isoc_threads" = yes; then + gl_STDTHREADLIB_BODY + LIBTHREAD=$LIBSTDTHREAD LTLIBTHREAD=$LIBSTDTHREAD + LIBMULTITHREAD=$LIBSTDTHREAD LTLIBMULTITHREAD=$LIBSTDTHREAD + gl_threads_api=isoc + AC_DEFINE([USE_ISOC_THREADS], [1], + [Define if the ISO C multithreading library can be used.]) + fi + fi + if test $gl_threads_api = none; then + case "$gl_use_threads" in + yes | windows | win32) # The 'win32' is for backward compatibility. + if { case "$host_os" in + mingw*) true;; + *) false;; + esac + }; then + gl_threads_api=windows + AC_DEFINE([USE_WINDOWS_THREADS], [1], + [Define if the native Windows multithreading API can be used.]) + fi + ;; + esac + fi + fi + AC_MSG_CHECKING([for multithread API to use]) + AC_MSG_RESULT([$gl_threads_api]) + AC_SUBST([LIBTHREAD]) + AC_SUBST([LTLIBTHREAD]) + AC_SUBST([LIBMULTITHREAD]) + AC_SUBST([LTLIBMULTITHREAD]) +]) + +AC_DEFUN([gl_THREADLIB], +[ + AC_REQUIRE([gl_THREADLIB_EARLY]) + AC_REQUIRE([gl_THREADLIB_BODY]) +]) + + +dnl gl_DISABLE_THREADS +dnl ------------------ +dnl Sets the gl_THREADLIB default so that threads are not used by default. +dnl The user can still override it at installation time, by using the +dnl configure option '--enable-threads'. + +AC_DEFUN([gl_DISABLE_THREADS], [ + m4_divert_text([INIT_PREPARE], [gl_use_threads_default=no]) +]) + + +dnl gl_AVOID_WINPTHREAD +dnl ------------------- +dnl Sets the gl_THREADLIB default so that on mingw, a dependency to the +dnl libwinpthread DLL (mingw-w64 winpthreads library) is avoided. +dnl The user can still override it at installation time, by using the +dnl configure option '--enable-threads'. + +AC_DEFUN([gl_AVOID_WINPTHREAD], [ + m4_divert_text([INIT_PREPARE], [gl_use_winpthreads_default=no]) +]) + + +dnl ============================================================================ + + +dnl Survey of platforms: +dnl +dnl Platform Available Compiler Supports test-lock +dnl flavours option weak result +dnl --------------- --------- --------- -------- --------- +dnl Linux 2.4/glibc posix -lpthread Y OK +dnl +dnl Linux/glibc 2.34 posix Y OK +dnl +dnl GNU Hurd/glibc posix -lpthread Y OK +dnl +dnl Ubuntu 14.04 posix -pthread Y OK +dnl +dnl FreeBSD 5.3 posix -lc_r Y +dnl posix -lkse ? Y +dnl posix -lpthread ? Y +dnl posix -lthr Y +dnl +dnl FreeBSD 5.2 posix -lc_r Y +dnl posix -lkse Y +dnl posix -lthr Y +dnl +dnl FreeBSD 4.0,4.10 posix -lc_r Y OK +dnl +dnl NetBSD 1.6 -- +dnl +dnl OpenBSD 3.4 posix -lpthread Y OK +dnl +dnl Mac OS X 10.[123] posix -lpthread Y OK +dnl +dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK +dnl +dnl HP-UX 11 posix -lpthread N (cc) OK +dnl Y (gcc) +dnl +dnl IRIX 6.5 posix -lpthread Y 0.5 +dnl +dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK +dnl +dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK +dnl -lpthread (gcc) Y +dnl +dnl Cygwin posix -lpthread Y OK +dnl +dnl Mingw windows N OK +dnl +dnl BeOS 5 -- +dnl +dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is +dnl turned off: +dnl OK if all three tests terminate OK, +dnl 0.5 if the first test terminates OK but the second one loops endlessly, +dnl 0.0 if the first test already loops endlessly. |