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m4/threadlib.m4
622 строки
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Evgeny Grin (Karlson2k)
Updated M4 macros
18 янв 2021, 23:24
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18 янв 2021, 23:24
3b64c6b
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# threadlib.m4 serial 29 dnl Copyright (C) 2005-2021 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], [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 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*) : > 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 LIB_SCHED_YIELD 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 # 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], [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 solaris | solaris2.[1-9] | solaris2.[1-9].* | hpux*) AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1], [Define if the pthread_in_use() detection is hard.]) esac ]) 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 $gl_pthread_api != yes; then # For FreeBSD 4. AC_CHECK_LIB([c_r], [pthread_kill], [gl_pthread_api=yes LIBPTHREAD=-lc_r LIBPMULTITHREAD=-lc_r]) fi fi fi AC_MSG_CHECKING([whether POSIX threads API is available]) AC_MSG_RESULT([$gl_pthread_api]) AC_SUBST([LIBPTHREAD]) AC_SUBST([LIBPMULTITHREAD]) if test $gl_pthread_api = yes; then AC_DEFINE([HAVE_PTHREAD_API], [1], [Define if you have the <pthread.h> header and the POSIX threads API.]) fi dnl On some systems, sched_yield is in librt, rather than in libpthread. AC_LINK_IFELSE( [AC_LANG_PROGRAM( [[#include <sched.h>]], [[sched_yield ();]])], [LIB_SCHED_YIELD= ], [dnl Solaris 7...10 has sched_yield in librt, not in libpthread or libc. AC_CHECK_LIB([rt], [sched_yield], [LIB_SCHED_YIELD=-lrt], [dnl Solaris 2.5.1, 2.6 has sched_yield in libposix4, not librt. AC_CHECK_LIB([posix4], [sched_yield], [LIB_SCHED_YIELD=-lposix4])]) ]) AC_SUBST([LIB_SCHED_YIELD]) gl_pthreadlib_body_done=done fi ]) AC_DEFUN([gl_PTHREADLIB], [ AC_REQUIRE([gl_ANYTHREADLIB_EARLY]) gl_PTHREADLIB_BODY ]) dnl ============================================================================ dnl Macros for the ISO C API dnl gl_STDTHREADLIB dnl --------------- dnl Tests for the libraries needs for using the ISO C threads API. dnl Sets the variable LIBSTDTHREAD to the linker options for use in a Makefile. dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for dnl multithread-safe programs. dnl Defines the C macro HAVE_THREADS_H if (at least parts of) the ISO C threads dnl API is available. dnl The guts of gl_STDTHREADLIB. Needs to be expanded only once. AC_DEFUN([gl_STDTHREADLIB_BODY], [ AC_REQUIRE([gl_ANYTHREADLIB_EARLY]) AC_REQUIRE([AC_CANONICAL_HOST]) if test -z "$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 AIX >= 7.1 and Solaris >= 11.4 have thrd_create in libc. AC_CHECK_FUNCS([thrd_create]) 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 $LIB_SCHED_YIELD" fi ;; esac AC_SUBST([LIBSTDTHREAD]) AC_MSG_CHECKING([whether ISO C threads API is available]) AC_MSG_RESULT([$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 "$gl_have_isoc_threads" = yes; then gl_threads_api='isoc+posix' AC_DEFINE([USE_ISOC_AND_POSIX_THREADS], [1], [Define if the combination of the ISO C and POSIX multithreading APIs can be used.]) LIBTHREAD= LTLIBTHREAD= else gl_threads_api=posix AC_DEFINE([USE_POSIX_THREADS], [1], [Define if the POSIX multithreading library can be used.]) if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then if case "$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 "$host_os" in freebsd* | dragonfly*) if test "x$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 GNU Hurd/glibc posix 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.