[PATCH] gethrxtime: don’t use nanouptime, microuptime

* lib/gethrxtime.c (gethrxtime): On platforms with
CLOCK_MONOTONIC, try it first.  If it fails, just fall back on
CLOCK_REALTIME as that’s what current_timespec would do anyway.
On platforms lacking CLOCK_MONOTONIC, just use current_timespec.
* m4/gethrxtime.m4 (gl_GETHRXTIME): Don’t check for microuptime or
nanouptime.  They aren’t exposed to user space by BSD kernels now,
and it’s not clear that they ever were.
---
 ChangeLog        | 11 +++++++++++
 lib/gethrxtime.c | 40 +++++++++-------------------------------
 m4/gethrxtime.m4 |  6 ++----
 3 files changed, 22 insertions(+), 35 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6fd9e8ce38..6ee89378ea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2026-06-20  Paul Eggert  <[email protected]>
+
+	gethrxtime: don’t use nanouptime, microuptime
+	* lib/gethrxtime.c (gethrxtime): On platforms with
+	CLOCK_MONOTONIC, try it first.  If it fails, just fall back on
+	CLOCK_REALTIME as that’s what current_timespec would do anyway.
+	On platforms lacking CLOCK_MONOTONIC, just use current_timespec.
+	* m4/gethrxtime.m4 (gl_GETHRXTIME): Don’t check for microuptime or
+	nanouptime.  They aren’t exposed to user space by BSD kernels now,
+	and it’s not clear that they ever were.
+
 2026-06-19  Paul Eggert  <[email protected]>
 
 	fstatat: don’t mess with CFLAGS
diff --git a/lib/gethrxtime.c b/lib/gethrxtime.c
index e1580b3d72..72678b6f65 100644
--- a/lib/gethrxtime.c
+++ b/lib/gethrxtime.c
@@ -34,39 +34,17 @@
 xtime_t
 gethrxtime (void)
 {
-# if HAVE_NANOUPTIME
-  {
-    struct timespec ts;
-    nanouptime (&ts);
-    return xtime_make (ts.tv_sec, ts.tv_nsec);
-  }
+  struct timespec ts;
+# if defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME
+  /* If available, use a monotonically increasing clock.
+     Otherwise fall back on CLOCK_REALTIME as that is
+     what current_timespec would do anyway.  */
+  if (clock_gettime (CLOCK_MONOTONIC, &ts) < 0)
+    clock_gettime (CLOCK_REALTIME, &ts);
 # else
-
-#  if defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME
-  {
-    struct timespec ts;
-    if (clock_gettime (CLOCK_MONOTONIC, &ts) == 0)
-      return xtime_make (ts.tv_sec, ts.tv_nsec);
-  }
-#  endif
-
-#  if HAVE_MICROUPTIME
-  {
-    struct timeval tv;
-    microuptime (&tv);
-    return xtime_make (tv.tv_sec, 1000 * tv.tv_usec);
-  }
-
-#  else
-  /* No monotonically increasing clocks are available; fall back on a
-     clock that might jump backwards, since it's the best we can do.  */
-  {
-    struct timespec ts;
-    gettime (&ts);
-    return xtime_make (ts.tv_sec, ts.tv_nsec);
-  }
-#  endif
+  ts = current_timespec ();
 # endif
+  return xtime_make (ts.tv_sec, ts.tv_nsec);
 }
 
 #endif
diff --git a/m4/gethrxtime.m4 b/m4/gethrxtime.m4
index e141cfaef5..918437f8df 100644
--- a/m4/gethrxtime.m4
+++ b/m4/gethrxtime.m4
@@ -20,10 +20,8 @@ AC_DEFUN([gl_GETHRXTIME],
     dnl Find libraries needed to link lib/gethrxtime.c.
     AC_REQUIRE([gl_CLOCK_TIME])
     AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
-    AC_CHECK_FUNCS_ONCE([microuptime nanouptime])
-    if test $ac_cv_func_nanouptime != yes \
-       && { test $ac_cv_have_decl_gethrtime = no \
-            || test $gl_cv_arithmetic_hrtime_t = no; }; then
+    if { test $ac_cv_have_decl_gethrtime = no \
+         || test $gl_cv_arithmetic_hrtime_t = no; }; then
       AC_CACHE_CHECK([whether CLOCK_MONOTONIC or CLOCK_REALTIME is defined],
         [gl_cv_have_clock_gettime_macro],
         [AC_EGREP_CPP([have_clock_gettime_macro],
-- 
2.53.0