diff --git a/ChangeLog b/ChangeLog
index 46a70ff7ce..385deb472f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,51 @@
+2017-06-22  Mike Crowe  <mac@mcrowe.com>
+
+	* sysdeps/nptl/pthread.h: Add pthread_cond_timedwaitonclock_np
+	declaration
+	* nptl/pthread_cond.c:
+	(__pthread_cond_wait_common): Add clockid parameter to determine
+	which clock to use.
+	(__pthread_cond_wait): Add dummy clockid parameter when calling
+	__pthread_cond_wait_common.
+	(__pthread_cond_timedwait): Read default clock set during
+	pthread_cond_init to supply as clockid parameter in call to
+	__pthread_cond_wait_common.
+	(__pthread_cond_timedwaitonclock_np): New function that supports
+	specifying clock to use at call time rather than initialisation
+	time.
+	(pthread_cond_timdwaitonclock_np): Weak alias for
+	__pthread_cond_timedwaitonclock_np
+	* nptl/tst-cond5-onclock.c: New file to test
+	pthread_cond_timedwaitonclock_np
+	* nptl/tst-cond11-onclock.c: New file to test
+	pthread_cond_timedwaitonclock_np
+	* nptl/Makefile: Add tst-cond5-onclock and tst-cond11-onclock
+	* nptl/Versions (GLIBC_2.26): Add pthread_cond_timedwaitonclock_np
+	to both libc and libpthread
+	* nptl/pthread_functions.h: Add
+	ptr___pthread_cond_timedwaitonclock_np
+	* nptl/forward.c (pthread_functions): Forward
+	pthread_cond_timedwaitonclock_np from libc to libpthread3
+	* nptl/nptl-init.c: Forwarding function initialisation for
+	pthread_cond_timedwaitonclock_np
+	* nptl/pthreadP.h (__pthread_cond_timedwait_np): Add
+	* manual/threads.texi: Add documentation for
+	pthread_cond_timedwaitonclock_np
+	* sysdeps/unix/sysv/linux/aarch64/libc.abilist: Add
+	pthread_cond_timedwaitonclock_np
+	* sysdeps/unix/sysv/linux/arm/libc.abilist: Likewise
+	* sysdeps/unix/sysv/linux/arm/libpthread.abilist: Likewise
+	* sysdeps/unix/sysv/linux/i386/libc.abilist: Likewise
+	* sysdeps/unix/sysv/linux/i386/libpthread.abilist: Likewise
+	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist: Likewise
+	* sysdeps/unix/sysv/linux/m68k/coldfire/libpthread.abilist: Likewise
+	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist: Likewise
+	* sysdeps/unix/sysv/linux/m68k/m680x0/libpthread.abilist: Likewise
+	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise
+	* sysdeps/unix/sysv/linux/x86_64/64/libpthread.abilist: Likewise
+	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise
+	* sysdeps/unix/sysv/linux/x86_64/x32/libpthread.abilist: Likewise
+
 2017-06-21  Florian Weimer  <fweimer@redhat.com>
 
 	* intl/loadmsgcat.c: Remove alloca support.
diff --git a/manual/threads.texi b/manual/threads.texi
index 769d974d50..8b3652c859 100644
--- a/manual/threads.texi
+++ b/manual/threads.texi
@@ -124,6 +124,27 @@ The system does not have sufficient memory.
 @end table
 @end deftypefun
 
+@comment pthread.h
+@comment GNU
+@deftypefun int pthread_cond_timedwaitonclock_np (pthread_cond_t *@var{cond}, pthread_mutex_t *@var{mutex},
+                                                  clockid_t @var{clockid}, const struct timespec *@var{abstime})
+@safety{@prelim{}@mtsafe{}@asunsafe{@asulock{}}@acunsafe{@aculock}}
+@c If exactly the same function with arguments is called from a signal
+@c handler that interrupts between the mutex unlock and sleep then it
+@c will unlock the mutex twice resulting in undefined behaviour. Keep
+@c in mind that the unlock and sleep are only atomic with respect to other
+@c threads (really a happens-after relationship for pthread_cond_broadcast
+@c and pthread_cond_signal).
+@c In the AC case we would cancel the thread and the mutex would remain
+@c locked and we can't recover from that.
+Behaves like POSIX @code{pthread_cond_timedwait} except the time
+@var{abstime} is measured against the clock specified by @var{clockid}
+rather than the clock specified or defaulted when @code{pthread_cond_init}
+was called. Currently, @code{clockid} must be either @code{CLOCK_MONOTONIC}
+or @code{CLOCK_REALTIME}. This variant is necessary in order to implement
+C++11's @code{std::condition_variable::wait_until} method correctly.
+@end deftypefun
+
 @c FIXME these are undocumented:
 @c pthread_atfork
 @c pthread_attr_destroy
diff --git a/nptl/Makefile b/nptl/Makefile
index 853da72e74..8cf661dc64 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -235,8 +235,8 @@ tests = tst-attr1 tst-attr2 tst-attr3 tst-default-attr \
 	tst-mutexpi5a tst-mutexpi6 tst-mutexpi7 tst-mutexpi7a \
 	tst-mutexpi9 \
 	tst-spin1 tst-spin2 tst-spin3 tst-spin4 \
-	tst-cond1 tst-cond2 tst-cond3 tst-cond4 tst-cond5 tst-cond6 tst-cond7 \
-	tst-cond8 tst-cond9 tst-cond10 tst-cond11 tst-cond12 tst-cond13 \
+	tst-cond1 tst-cond2 tst-cond3 tst-cond4 tst-cond5 tst-cond5-onclock tst-cond6 tst-cond7 \
+	tst-cond8 tst-cond9 tst-cond10 tst-cond11 tst-cond11-onclock tst-cond12 tst-cond13 \
 	tst-cond14 tst-cond15 tst-cond16 tst-cond17 tst-cond18 tst-cond19 \
 	tst-cond20 tst-cond21 tst-cond22 tst-cond23 tst-cond24 tst-cond25 \
 	tst-cond-except \
diff --git a/nptl/Versions b/nptl/Versions
index 0ae5def464..1cf8c2fbad 100644
--- a/nptl/Versions
+++ b/nptl/Versions
@@ -28,6 +28,9 @@ libc {
     pthread_cond_wait; pthread_cond_signal;
     pthread_cond_broadcast; pthread_cond_timedwait;
   }
+  GLIBC_2.26 {
+    pthread_cond_timedwaitonclock_np;
+  }
   GLIBC_PRIVATE {
     __libc_alloca_cutoff;
     # Internal libc interface to libpthread
@@ -265,6 +268,10 @@ libpthread {
   GLIBC_2.22 {
   }
 
+  GLIBC_2.26 {
+    pthread_cond_timedwaitonclock_np;
+  }
+
   GLIBC_PRIVATE {
     __pthread_initialize_minimal;
     __pthread_clock_gettime; __pthread_clock_settime;
diff --git a/nptl/forward.c b/nptl/forward.c
index ac96765f29..c5fcb2f066 100644
--- a/nptl/forward.c
+++ b/nptl/forward.c
@@ -164,6 +164,11 @@ FORWARD (__pthread_cond_timedwait,
 	  const struct timespec *abstime), (cond, mutex, abstime), 0)
 versioned_symbol (libc, __pthread_cond_timedwait, pthread_cond_timedwait,
 		  GLIBC_2_3_2);
+FORWARD (__pthread_cond_timedwaitonclock_np,
+	 (pthread_cond_t *cond, pthread_mutex_t *mutex, clockid_t clockid,
+	  const struct timespec *abstime), (cond, mutex, clockid, abstime),
+	 0)
+weak_alias (__pthread_cond_timedwaitonclock_np, pthread_cond_timedwaitonclock_np);
 
 
 FORWARD (pthread_equal, (pthread_t thread1, pthread_t thread2),
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 29216077a2..b913515fe9 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -106,6 +106,7 @@ static const struct pthread_functions pthread_functions =
     .ptr___pthread_cond_signal = __pthread_cond_signal,
     .ptr___pthread_cond_wait = __pthread_cond_wait,
     .ptr___pthread_cond_timedwait = __pthread_cond_timedwait,
+    .ptr___pthread_cond_timedwaitonclock_np = __pthread_cond_timedwaitonclock_np,
 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2)
     .ptr___pthread_cond_broadcast_2_0 = __pthread_cond_broadcast_2_0,
     .ptr___pthread_cond_destroy_2_0 = __pthread_cond_destroy_2_0,
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index 7fc1e50f78..c7e7587479 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -488,6 +488,10 @@ extern int __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex);
 extern int __pthread_cond_timedwait (pthread_cond_t *cond,
 				     pthread_mutex_t *mutex,
 				     const struct timespec *abstime);
+extern int __pthread_cond_timedwaitonclock_np (pthread_cond_t *cond,
+					       pthread_mutex_t *mutex,
+					       clockid_t clockid,
+					       const struct timespec *abstime);
 extern int __pthread_condattr_destroy (pthread_condattr_t *attr);
 extern int __pthread_condattr_init (pthread_condattr_t *attr);
 extern int __pthread_key_create (pthread_key_t *key, void (*destr) (void *));
diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
index 7812b94a3a..d0166b86d5 100644
--- a/nptl/pthread_cond_wait.c
+++ b/nptl/pthread_cond_wait.c
@@ -378,6 +378,7 @@ __condvar_cleanup_waiting (void *arg)
 */
 static __always_inline int
 __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
+    clockid_t clockid,
     const struct timespec *abstime)
 {
   const int maxspin = 0;
@@ -510,7 +511,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
 	      if (__glibc_unlikely (abstime->tv_sec < 0))
 	        err = ETIMEDOUT;
 
-	      else if ((flags & __PTHREAD_COND_CLOCK_MONOTONIC_MASK) != 0)
+	      else if (clockid == CLOCK_MONOTONIC)
 		{
 		  /* CLOCK_MONOTONIC is requested.  */
 		  struct timespec rt;
@@ -652,7 +653,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
 int
 __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
 {
-  return __pthread_cond_wait_common (cond, mutex, NULL);
+  return __pthread_cond_wait_common (cond, mutex, CLOCK_REALTIME, NULL);
 }
 
 /* See __pthread_cond_wait_common.  */
@@ -664,10 +665,31 @@ __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
      it can assume that abstime is not NULL.  */
   if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
     return EINVAL;
-  return __pthread_cond_wait_common (cond, mutex, abstime);
+
+  clockid_t clockid = ((cond->__data.__wrefs & __PTHREAD_COND_CLOCK_MONOTONIC_MASK) != 0) ? CLOCK_MONOTONIC : CLOCK_REALTIME;
+  return __pthread_cond_wait_common (cond, mutex, clockid, abstime);
+}
+
+/* See __pthread_cond_wait_common.  */
+int
+__pthread_cond_timedwaitonclock_np (pthread_cond_t *cond, pthread_mutex_t *mutex,
+				    clockid_t clockid,
+				    const struct timespec *abstime)
+{
+  /* Check parameter validity.  This should also tell the compiler that
+     it can assume that abstime is not NULL.  */
+  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+    return EINVAL;
+
+  /* We only support CLOCK_REALTIME and CLOCK_MONOTONIC */
+  if (clockid != CLOCK_REALTIME && clockid != CLOCK_MONOTONIC)
+    return EINVAL;
+
+  return __pthread_cond_wait_common (cond, mutex, clockid, abstime);
 }
 
 versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
 		  GLIBC_2_3_2);
 versioned_symbol (libpthread, __pthread_cond_timedwait, pthread_cond_timedwait,
 		  GLIBC_2_3_2);
+weak_alias (__pthread_cond_timedwaitonclock_np, pthread_cond_timedwaitonclock_np);
diff --git a/nptl/tst-cond11-onclock.c b/nptl/tst-cond11-onclock.c
new file mode 100644
index 0000000000..439cd404de
--- /dev/null
+++ b/nptl/tst-cond11-onclock.c
@@ -0,0 +1,209 @@
+/* Test pthread_cond_timedwaitonclock_np, based on tst-cond11.c
+   Copyright (C) 2003-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Mike Crowe <mac@mcrowe.com>, 2015.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <time.h>
+#include <unistd.h>
+
+
+#if defined _POSIX_CLOCK_SELECTION && _POSIX_CLOCK_SELECTION >= 0
+static int
+run_test (clockid_t attr_clock, clockid_t wait_clock)
+{
+  pthread_condattr_t condattr;
+  pthread_cond_t cond;
+  pthread_mutexattr_t mutattr;
+  pthread_mutex_t mut;
+
+  printf ("attr_clock = %d, wait_clock = %d\n", (int) attr_clock, (int) wait_clock);
+
+  if (pthread_condattr_init (&condattr) != 0)
+    {
+      puts ("condattr_init failed");
+      return 1;
+    }
+
+  if (pthread_condattr_setclock (&condattr, attr_clock) != 0)
+    {
+      puts ("condattr_setclock failed");
+      return 1;
+    }
+
+  clockid_t cl2;
+  if (pthread_condattr_getclock (&condattr, &cl2) != 0)
+    {
+      puts ("condattr_getclock failed");
+      return 1;
+    }
+  if (attr_clock != cl2)
+    {
+      printf ("condattr_getclock returned wrong value: %d, expected %d\n",
+	      (int) cl2, (int) attr_clock);
+      return 1;
+    }
+
+  if (pthread_cond_init (&cond, &condattr) != 0)
+    {
+      puts ("cond_init failed");
+      return 1;
+    }
+
+  if (pthread_condattr_destroy (&condattr) != 0)
+    {
+      puts ("condattr_destroy failed");
+      return 1;
+    }
+
+  if (pthread_mutexattr_init (&mutattr) != 0)
+    {
+      puts ("mutexattr_init failed");
+      return 1;
+    }
+
+  if (pthread_mutexattr_settype (&mutattr, PTHREAD_MUTEX_ERRORCHECK) != 0)
+    {
+      puts ("mutexattr_settype failed");
+      return 1;
+    }
+
+  if (pthread_mutex_init (&mut, &mutattr) != 0)
+    {
+      puts ("mutex_init failed");
+      return 1;
+    }
+
+  if (pthread_mutexattr_destroy (&mutattr) != 0)
+    {
+      puts ("mutexattr_destroy failed");
+      return 1;
+    }
+
+  if (pthread_mutex_lock (&mut) != 0)
+    {
+      puts ("mutex_lock failed");
+      return 1;
+    }
+
+  if (pthread_mutex_lock (&mut) != EDEADLK)
+    {
+      puts ("2nd mutex_lock did not return EDEADLK");
+      return 1;
+    }
+
+  struct timespec ts;
+  if (clock_gettime (wait_clock, &ts) != 0)
+    {
+      puts ("clock_gettime failed");
+      return 1;
+    }
+
+  /* Wait one second.  */
+  ++ts.tv_sec;
+
+  int e = pthread_cond_timedwaitonclock_np (&cond, &mut, wait_clock, &ts);
+  if (e == 0)
+    {
+      puts ("cond_timedwait succeeded");
+      return 1;
+    }
+  else if (e != ETIMEDOUT)
+    {
+      puts ("cond_timedwait did not return ETIMEDOUT");
+      return 1;
+    }
+
+  struct timespec ts2;
+  if (clock_gettime (wait_clock, &ts2) != 0)
+    {
+      puts ("second clock_gettime failed");
+      return 1;
+    }
+
+  if (ts2.tv_sec < ts.tv_sec
+      || (ts2.tv_sec == ts.tv_sec && ts2.tv_nsec < ts.tv_nsec))
+    {
+      puts ("timeout too short");
+      return 1;
+    }
+
+  if (pthread_mutex_unlock (&mut) != 0)
+    {
+      puts ("mutex_unlock failed");
+      return 1;
+    }
+
+  if (pthread_mutex_destroy (&mut) != 0)
+    {
+      puts ("mutex_destroy failed");
+      return 1;
+    }
+
+  if (pthread_cond_destroy (&cond) != 0)
+    {
+      puts ("cond_destroy failed");
+      return 1;
+    }
+
+  return 0;
+}
+#endif
+
+
+static int
+do_test (void)
+{
+#if !defined _POSIX_CLOCK_SELECTION || _POSIX_CLOCK_SELECTION == -1
+
+  puts ("_POSIX_CLOCK_SELECTION not supported, test skipped");
+  return 0;
+
+#else
+
+  int res = run_test (CLOCK_REALTIME, CLOCK_REALTIME);
+
+# if defined _POSIX_MONOTONIC_CLOCK && _POSIX_MONOTONIC_CLOCK >= 0
+#  if _POSIX_MONOTONIC_CLOCK == 0
+  int e = sysconf (_SC_MONOTONIC_CLOCK);
+  if (e < 0)
+    puts ("CLOCK_MONOTONIC not supported");
+  else if (e == 0)
+    {
+      puts ("sysconf (_SC_MONOTONIC_CLOCK) must not return 0");
+      res = 1;
+    }
+  else
+#  endif
+    {
+      res |= run_test (CLOCK_REALTIME, CLOCK_MONOTONIC);
+      res |= run_test (CLOCK_MONOTONIC, CLOCK_MONOTONIC);
+      res |= run_test (CLOCK_MONOTONIC, CLOCK_REALTIME);
+    }
+# else
+  puts ("_POSIX_MONOTONIC_CLOCK not defined");
+# endif
+
+  return res;
+#endif
+}
+
+#define TIMEOUT 12
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/nptl/tst-cond5-onclock.c b/nptl/tst-cond5-onclock.c
new file mode 100644
index 0000000000..adb3342781
--- /dev/null
+++ b/nptl/tst-cond5-onclock.c
@@ -0,0 +1,114 @@
+/* Test pthread_cond_timedwaitonclock_np, based on tst-cond5.c
+   Copyright (C) 2002-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Mike Crowe <mac@mcrowe.com>, 2015.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <sys/time.h>
+
+
+static pthread_mutex_t mut;
+static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+
+
+static int
+do_test_onclock(clockid_t clockid)
+{
+  pthread_mutexattr_t ma;
+  int err;
+  struct timespec ts;
+
+  if (pthread_mutexattr_init (&ma) != 0)
+    {
+      puts ("mutexattr_init failed");
+      exit (1);
+    }
+
+  if (pthread_mutexattr_settype (&ma, PTHREAD_MUTEX_ERRORCHECK) != 0)
+    {
+      puts ("mutexattr_settype failed");
+      exit (1);
+    }
+
+  if (pthread_mutex_init (&mut, &ma) != 0)
+    {
+      puts ("mutex_init failed");
+      exit (1);
+    }
+
+  /* Get the mutex.  */
+  if (pthread_mutex_lock (&mut) != 0)
+    {
+      puts ("mutex_lock failed");
+      exit (1);
+    }
+
+  /* Waiting for the condition will fail.  But we want the timeout here.  */
+  if (clock_gettime (clockid, &ts) != 0)
+    {
+      puts ("clock_gettime failed");
+      exit (1);
+    }
+
+  ts.tv_nsec += 500000000;
+  if (ts.tv_nsec >= 1000000000)
+    {
+      ts.tv_nsec -= 1000000000;
+      ++ts.tv_sec;
+    }
+  err = pthread_cond_timedwaitonclock_np (&cond, &mut, clockid, &ts);
+  if (err == 0)
+    {
+      /* This could in theory happen but here without any signal and
+	 additional waiter it should not.  */
+      puts ("cond_timedwait succeeded");
+      exit (1);
+    }
+  else if (err != ETIMEDOUT)
+    {
+      printf ("cond_timedwait returned with %s\n", strerror (err));
+      exit (1);
+    }
+
+  err = pthread_mutex_unlock (&mut);
+  if (err != 0)
+    {
+      printf ("mutex_unlock failed: %s\n", strerror (err));
+      exit (1);
+    }
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  int rc;
+  rc = do_test_onclock(CLOCK_MONOTONIC);
+  if (rc == 0)
+    rc = do_test_onclock(CLOCK_REALTIME);
+
+  return rc;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/sysdeps/nptl/pthread-functions.h b/sysdeps/nptl/pthread-functions.h
index 4006fc6c25..8225fdbfca 100644
--- a/sysdeps/nptl/pthread-functions.h
+++ b/sysdeps/nptl/pthread-functions.h
@@ -55,6 +55,10 @@ struct pthread_functions
   int (*ptr___pthread_cond_wait) (pthread_cond_t *, pthread_mutex_t *);
   int (*ptr___pthread_cond_timedwait) (pthread_cond_t *, pthread_mutex_t *,
 				       const struct timespec *);
+  int (*ptr___pthread_cond_timedwaitonclock_np) (pthread_cond_t *,
+						 pthread_mutex_t *,
+						 clockid_t,
+						 const struct timespec *);
   int (*ptr___pthread_cond_broadcast_2_0) (pthread_cond_2_0_t *);
   int (*ptr___pthread_cond_destroy_2_0) (pthread_cond_2_0_t *);
   int (*ptr___pthread_cond_init_2_0) (pthread_cond_2_0_t *,
diff --git a/sysdeps/nptl/pthread.h b/sysdeps/nptl/pthread.h
index 632ea7bc36..e95df8f592 100644
--- a/sysdeps/nptl/pthread.h
+++ b/sysdeps/nptl/pthread.h
@@ -1003,6 +1003,21 @@ extern int pthread_cond_timedwait (pthread_cond_t *__restrict __cond,
 				   const struct timespec *__restrict __abstime)
      __nonnull ((1, 2, 3));
 
+#ifdef __USE_GNU
+/* Wait for condition variable COND to be signaled or broadcast until
+   ABSTIME measured by the specified clock. MUTEX is assumed to be
+   locked before. CLOCK is the clock to use. ABSTIME is an absolute
+   time specification against CLOCK's epoch.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW. */
+extern int pthread_cond_timedwaitonclock_np (pthread_cond_t *__restrict __cond,
+					     pthread_mutex_t *__restrict __mutex,
+					     __clockid_t __clock_id,
+					     const struct timespec *__restrict __abstime)
+     __nonnull ((1, 2, 4));
+#endif
+
 /* Functions for handling condition variable attributes.  */
 
 /* Initialize condition variable attribute ATTR.  */
diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
index d2a206a8df..b0ecb71d3b 100644
--- a/sysdeps/unix/sysv/linux/arm/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
@@ -101,6 +101,7 @@ GLIBC_2.25 strfroml F
 GLIBC_2.26 GLIBC_2.26 A
 GLIBC_2.26 preadv2 F
 GLIBC_2.26 preadv64v2 F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.26 pwritev2 F
 GLIBC_2.26 pwritev64v2 F
 GLIBC_2.26 reallocarray F
diff --git a/sysdeps/unix/sysv/linux/arm/libpthread.abilist b/sysdeps/unix/sysv/linux/arm/libpthread.abilist
index 91545c1542..32b3331c19 100644
--- a/sysdeps/unix/sysv/linux/arm/libpthread.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libpthread.abilist
@@ -9,6 +9,7 @@ GLIBC_2.12 pthread_setname_np F
 GLIBC_2.18 GLIBC_2.18 A
 GLIBC_2.18 pthread_getattr_default_np F
 GLIBC_2.18 pthread_setattr_default_np F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 _IO_flockfile F
 GLIBC_2.4 _IO_ftrylockfile F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index 2ff1998ac9..1bcf512fa1 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2023,6 +2023,7 @@ GLIBC_2.25 strfroml F
 GLIBC_2.26 GLIBC_2.26 A
 GLIBC_2.26 preadv2 F
 GLIBC_2.26 preadv64v2 F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.26 pwritev2 F
 GLIBC_2.26 pwritev64v2 F
 GLIBC_2.26 reallocarray F
diff --git a/sysdeps/unix/sysv/linux/i386/libpthread.abilist b/sysdeps/unix/sysv/linux/i386/libpthread.abilist
index 8f9c3254be..3ae0e37475 100644
--- a/sysdeps/unix/sysv/linux/i386/libpthread.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libpthread.abilist
@@ -216,6 +216,7 @@ GLIBC_2.2.3 GLIBC_2.2.3 A
 GLIBC_2.2.3 pthread_getattr_np F
 GLIBC_2.2.6 GLIBC_2.2.6 A
 GLIBC_2.2.6 __nanosleep F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.3.2 GLIBC_2.3.2 A
 GLIBC_2.3.2 pthread_cond_broadcast F
 GLIBC_2.3.2 pthread_cond_destroy F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libpthread.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libpthread.abilist
index 91545c1542..32b3331c19 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libpthread.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libpthread.abilist
@@ -9,6 +9,7 @@ GLIBC_2.12 pthread_setname_np F
 GLIBC_2.18 GLIBC_2.18 A
 GLIBC_2.18 pthread_getattr_default_np F
 GLIBC_2.18 pthread_setattr_default_np F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 _IO_flockfile F
 GLIBC_2.4 _IO_ftrylockfile F
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libpthread.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libpthread.abilist
index 8f9c3254be..3ae0e37475 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libpthread.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libpthread.abilist
@@ -216,6 +216,7 @@ GLIBC_2.2.3 GLIBC_2.2.3 A
 GLIBC_2.2.3 pthread_getattr_np F
 GLIBC_2.2.6 GLIBC_2.2.6 A
 GLIBC_2.2.6 __nanosleep F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.3.2 GLIBC_2.3.2 A
 GLIBC_2.3.2 pthread_cond_broadcast F
 GLIBC_2.3.2 pthread_cond_destroy F
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index 513524d932..13f13e04db 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -1864,6 +1864,7 @@ GLIBC_2.25 strfroml F
 GLIBC_2.26 GLIBC_2.26 A
 GLIBC_2.26 preadv2 F
 GLIBC_2.26 preadv64v2 F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.26 pwritev2 F
 GLIBC_2.26 pwritev64v2 F
 GLIBC_2.26 reallocarray F
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libpthread.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libpthread.abilist
index 85365c057c..accb1d8d6f 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libpthread.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libpthread.abilist
@@ -203,6 +203,8 @@ GLIBC_2.2.5 waitpid F
 GLIBC_2.2.5 write F
 GLIBC_2.2.6 GLIBC_2.2.6 A
 GLIBC_2.2.6 __nanosleep F
+GLIBC_2.26 GLIBC_2.26 A
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.3.2 GLIBC_2.3.2 A
 GLIBC_2.3.2 pthread_cond_broadcast F
 GLIBC_2.3.2 pthread_cond_destroy F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
index 0c557e9f43..db930f6307 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2107,6 +2107,7 @@ GLIBC_2.25 strfroml F
 GLIBC_2.26 GLIBC_2.26 A
 GLIBC_2.26 preadv2 F
 GLIBC_2.26 preadv64v2 F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
 GLIBC_2.26 pwritev2 F
 GLIBC_2.26 pwritev64v2 F
 GLIBC_2.26 reallocarray F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libpthread.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libpthread.abilist
index 6cd0fc3487..d89762bd33 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libpthread.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libpthread.abilist
@@ -224,3 +224,4 @@ GLIBC_2.16 write F
 GLIBC_2.18 GLIBC_2.18 A
 GLIBC_2.18 pthread_getattr_default_np F
 GLIBC_2.18 pthread_setattr_default_np F
+GLIBC_2.26 pthread_cond_timedwaitonclock_np F
