+dnl Check for clock_gettime, nanosleep and sched_yield, used in the
+dnl implementation of 20.8.5 [time.clock], and 30.2.2 [thread.thread.this]
+dnl in the current C++0x working draft.
+dnl
+dnl --enable-libstdcxx-time
+dnl --enable-libstdcxx-time=yes
+dnl checks for the availability of monotonic and realtime clocks,
+dnl nanosleep and sched_yield in libc and libposix4 and, in case, links
+dnl the latter
+dnl --enable-libstdcxx-time=rt
+dnl also searches (and, in case, links) librt. Note that this is
+dnl not always desirable because, in glibc, for example, in turn it
+dnl triggers the linking of libpthread too, which activates locking,
+dnl a large overhead for single-thread programs.
+dnl --enable-libstdcxx-time=no
+dnl --disable-libstdcxx-time
+dnl disables the checks completely
+dnl
+AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME], [
+
+ AC_MSG_CHECKING([for clock_gettime, nanosleep and sched_yield])
+ GLIBCXX_ENABLE(libstdcxx-time,$1,[=KIND],
+ [use KIND for check type],
+ [permit yes|no|rt])
+
+ AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ ac_save_CXXFLAGS="$CXXFLAGS"
+ CXXFLAGS="$CXXFLAGS -fno-exceptions"
+ ac_save_LIBS="$LIBS"
+
+ ac_has_clock_monotonic=no
+ ac_has_clock_realtime=no
+ AC_MSG_RESULT($enable_libstdcxx_time)
+
+ if test x"$enable_libstdcxx_time" != x"no"; then
+
+ if test x"$enable_libstdcxx_time" = x"rt"; then
+ AC_SEARCH_LIBS(clock_gettime, [rt posix4])
+ AC_SEARCH_LIBS(nanosleep, [rt posix4])
+ else
+ AC_SEARCH_LIBS(clock_gettime, [posix4])
+ AC_SEARCH_LIBS(nanosleep, [posix4])
+ fi
+
+ case "$ac_cv_search_clock_gettime" in
+ -l*) GLIBCXX_LIBS=$ac_cv_search_clock_gettime
+ ;;
+ esac
+ case "$ac_cv_search_nanosleep" in
+ -l*) GLIBCXX_LIBS="$GLIBCXX_LIBS $ac_cv_search_nanosleep"
+ ;;
+ esac
+
+ AC_SEARCH_LIBS(sched_yield, [rt posix4])
+
+ case "$ac_cv_search_sched_yield" in
+ -lposix4*)
+ GLIBCXX_LIBS="$GLIBCXX_LIBS $ac_cv_search_sched_yield"
+ AC_DEFINE(_GLIBCXX_USE_SCHED_YIELD, 1,
+ [ Defined if sched_yield is available. ])
+ ;;
+ -lrt*)
+ if test x"$enable_libstdcxx_time" = x"rt"; then
+ GLIBCXX_LIBS="$GLIBCXX_LIBS $ac_cv_search_sched_yield"
+ AC_DEFINE(_GLIBCXX_USE_SCHED_YIELD, 1,
+ [ Defined if sched_yield is available. ])
+ fi
+ ;;
+ *)
+ AC_DEFINE(_GLIBCXX_USE_SCHED_YIELD, 1,
+ [ Defined if sched_yield is available. ])
+ ;;
+ esac
+
+ AC_CHECK_HEADERS(unistd.h, ac_has_unistd_h=yes, ac_has_unistd_h=no)
+
+ if test x"$ac_has_unistd_h" = x"yes"; then
+ AC_MSG_CHECKING([for monotonic clock])
+ AC_TRY_LINK(
+ [#include <unistd.h>
+ #include <time.h>
+ ],
+ [#if _POSIX_TIMERS > 0 && defined(_POSIX_MONOTONIC_CLOCK)
+ timespec tp;
+ #endif
+ clock_gettime(CLOCK_MONOTONIC, &tp);
+ ], [ac_has_clock_monotonic=yes], [ac_has_clock_monotonic=no])
+
+ AC_MSG_RESULT($ac_has_clock_monotonic)
+
+ AC_MSG_CHECKING([for realtime clock])
+ AC_TRY_LINK(
+ [#include <unistd.h>
+ #include <time.h>
+ ],
+ [#if _POSIX_TIMERS > 0
+ timespec tp;
+ #endif
+ clock_gettime(CLOCK_REALTIME, &tp);
+ ], [ac_has_clock_realtime=yes], [ac_has_clock_realtime=no])
+
+ AC_MSG_RESULT($ac_has_clock_realtime)
+
+ AC_MSG_CHECKING([for nanosleep])
+ AC_TRY_LINK(
+ [#include <unistd.h>
+ #include <time.h>
+ ],
+ [#if _POSIX_TIMERS > 0
+ timespec tp;
+ #endif
+ nanosleep(&tp, 0);
+ ], [ac_has_nanosleep=yes], [ac_has_nanosleep=no])
+
+ AC_MSG_RESULT($ac_has_nanosleep)
+ fi
+ fi
+
+ if test x"$ac_has_clock_monotonic" = x"yes"; then
+ AC_DEFINE(_GLIBCXX_USE_CLOCK_MONOTONIC, 1,
+ [ Defined if clock_gettime has monotonic clock support. ])
+ fi
+
+ if test x"$ac_has_clock_realtime" = x"yes"; then
+ AC_DEFINE(_GLIBCXX_USE_CLOCK_REALTIME, 1,
+ [ Defined if clock_gettime has realtime clock support. ])
+ fi
+
+ if test x"$ac_has_nanosleep" = x"yes"; then
+ AC_DEFINE(_GLIBCXX_USE_NANOSLEEP, 1,
+ [ Defined if nanosleep is available. ])
+ fi
+
+ AC_SUBST(GLIBCXX_LIBS)
+
+ CXXFLAGS="$ac_save_CXXFLAGS"
+ LIBS="$ac_save_LIBS"
+ AC_LANG_RESTORE
+])
+
+dnl
+dnl Check for gettimeofday, used in the implementation of 20.8.5
+dnl [time.clock] in the current C++0x working draft.
+dnl
+AC_DEFUN([GLIBCXX_CHECK_GETTIMEOFDAY], [
+
+ AC_MSG_CHECKING([for gettimeofday])
+
+ AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ ac_save_CXXFLAGS="$CXXFLAGS"
+ CXXFLAGS="$CXXFLAGS -fno-exceptions"
+
+ ac_has_gettimeofday=no;
+ AC_CHECK_HEADERS(sys/time.h, ac_has_sys_time_h=yes, ac_has_sys_time_h=no)
+ if test x"$ac_has_sys_time_h" = x"yes"; then
+ AC_MSG_CHECKING([for gettimeofday])
+ GCC_TRY_COMPILE_OR_LINK([#include <sys/time.h>],
+ [timeval tv; gettimeofday(&tv, 0);],
+ [ac_has_gettimeofday=yes], [ac_has_gettimeofday=no])
+
+ AC_MSG_RESULT($ac_has_gettimeofday)
+ fi
+
+ if test x"$ac_has_gettimeofday" = x"yes"; then
+ AC_DEFINE(_GLIBCXX_USE_GETTIMEOFDAY, 1,
+ [ Defined if gettimeofday is available. ])
+ fi
+
+ CXXFLAGS="$ac_save_CXXFLAGS"
+ AC_LANG_RESTORE
+])
+
+dnl