bpo-21302: Add clock_nanosleep() implementation for time.sleep()

Modules/timemodule.c

@@ -2053,7 +2053,11 @@ pysleep(_PyTime_t secs)
 {
     _PyTime_t deadline, monotonic;
 #ifndef MS_WINDOWS
+#ifdef HAVE_CLOCK_NANOSLEEP
+    struct timespec timeout_abs;
+#else
     struct timeval timeout;
+#endif
     int err = 0;
 #else
     _PyTime_t millisecs;
@@ -2066,14 +2070,24 @@ pysleep(_PyTime_t secs)
         return -1;
     }
     deadline = monotonic + secs;
+#ifdef HAVE_CLOCK_NANOSLEEP
+    if (_PyTime_AsTimespec(deadline, &timeout_abs) < 0)
+        return -1;
+#endif
 
     do {
 #ifndef MS_WINDOWS
+#ifndef HAVE_CLOCK_NANOSLEEP
         if (_PyTime_AsTimeval(secs, &timeout, _PyTime_ROUND_CEILING) < 0)
             return -1;
+#endif
 
         Py_BEGIN_ALLOW_THREADS
+#ifdef HAVE_CLOCK_NANOSLEEP
+        err = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &timeout_abs, NULL);
+#else
         err = select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout);
+#endif
         Py_END_ALLOW_THREADS
 
         if (err == 0)

configure

@@ -13237,6 +13237,64 @@ fi
 done
 
 
+for ac_func in clock_nanosleep
+do :
+  ac_fn_c_check_func "$LINENO" "clock_nanosleep" "ac_cv_func_clock_nanosleep"
+if test "x$ac_cv_func_clock_nanosleep" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_CLOCK_NANOSLEEP 1
+_ACEOF
+
+else
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for clock_nanosleep in -lrt" >&5
+$as_echo_n "checking for clock_nanosleep in -lrt... " >&6; }
+if ${ac_cv_lib_rt_clock_nanosleep+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lrt  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char clock_nanosleep ();
+int
+main ()
+{
+return clock_nanosleep ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_rt_clock_nanosleep=yes
+else
+  ac_cv_lib_rt_clock_nanosleep=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_rt_clock_nanosleep" >&5
+$as_echo "$ac_cv_lib_rt_clock_nanosleep" >&6; }
+if test "x$ac_cv_lib_rt_clock_nanosleep" = xyes; then :
+
+        $as_echo "#define HAVE_CLOCK_NANOSLEEP 1" >>confdefs.h
+
+
+fi
+
+
+fi
+done
+
+
 for ac_func in clock_getres
 do :
   ac_fn_c_check_func "$LINENO" "clock_getres" "ac_cv_func_clock_getres"

configure.ac

@@ -4086,6 +4086,12 @@ AC_CHECK_FUNCS(clock_gettime, [], [
     ])
 ])
 
+AC_CHECK_FUNCS(clock_nanosleep, [], [
+    AC_CHECK_LIB(rt, clock_nanosleep, [
+        AC_DEFINE(HAVE_CLOCK_NANOSLEEP, 1)
+    ])
+])
+
 AC_CHECK_FUNCS(clock_getres, [], [
     AC_CHECK_LIB(rt, clock_getres, [
         AC_DEFINE(HAVE_CLOCK_GETRES, 1)

pyconfig.h.in

@@ -136,6 +136,9 @@
 /* Define to 1 if you have the `clock' function. */
 #undef HAVE_CLOCK
 
+/* Define to 1 if you have the `clock_nanosleep' function. */
+#undef HAVE_CLOCK_NANOSLEEP
+
 /* Define to 1 if you have the `clock_getres' function. */
 #undef HAVE_CLOCK_GETRES