From 85422c2acba83852396c9d9fd22ff0493e3606fe Mon Sep 17 00:00:00 2001
From: Joseph Myers <joseph@codesourcery.com>
Date: Mon, 2 Nov 2015 18:54:19 +0000
Subject: [PATCH] Make nextafter, nexttoward set errno (bug 6799).

nextafter and nexttoward fail to set errno on overflow and underflow.
This patch makes them do so in cases that should include all the cases
where such errno setting is required by glibc's goals for when to set
errno (but not all cases of underflow where the result is nonzero and
so glibc's goals do not require errno setting).

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #6799]
	* math/s_nextafter.c: Include <errno.h>.
	(__nextafter): Set errno on overflow and underflow.
	* math/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/i386/fpu/s_nextafterl.c: Include <errno.h>.
	(__nextafterl): Set errno on overflow and underflow.
	* sysdeps/i386/fpu/s_nexttoward.c: Include <errno.h>.
	(__nexttoward): Set errno on overflow and underflow.
	* sysdeps/i386/fpu/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/ieee754/flt-32/s_nextafterf.c: Include <errno.h>.
	(__nextafterf): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128/s_nextafterl.c: Include <errno.h>.
	(__nextafterl): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128/s_nexttoward.c: Include <errno.h>.
	(__nexttoward): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c: Include <errno.h>.
	(__nextafterl): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c: Include <errno.h>.
	(__nexttoward): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-96/s_nexttoward.c: Include <errno.h>.
	(__nexttoward): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-96/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-opt/s_nexttowardfd.c: Include <errno.h>.
	(__nldbl_nexttowardf): Set errno on overflow and underflow.
	* sysdeps/m68k/m680x0/fpu/s_nextafterl.c: Include <errno.h>.
	(__nextafterl): Set errno on overflow and underflow.
	* math/libm-test.inc (nextafter_test_data): Do not allow errno
	setting to be missing on overflow.  Add more tests.
	(nexttoward_test_data): Likewise.
---
 ChangeLog                                   | 37 +++++++++++++++++++++
 NEWS                                        |  2 +-
 math/libm-test.inc                          | 20 +++++++----
 math/s_nextafter.c                          |  3 ++
 math/s_nexttowardf.c                        |  3 ++
 sysdeps/i386/fpu/s_nextafterl.c             |  3 ++
 sysdeps/i386/fpu/s_nexttoward.c             |  3 ++
 sysdeps/i386/fpu/s_nexttowardf.c            |  3 ++
 sysdeps/ieee754/flt-32/s_nextafterf.c       |  3 ++
 sysdeps/ieee754/ldbl-128/s_nextafterl.c     |  3 ++
 sysdeps/ieee754/ldbl-128/s_nexttoward.c     |  3 ++
 sysdeps/ieee754/ldbl-128/s_nexttowardf.c    |  3 ++
 sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c  |  5 +++
 sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c  |  3 ++
 sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c |  3 ++
 sysdeps/ieee754/ldbl-96/s_nexttoward.c      |  3 ++
 sysdeps/ieee754/ldbl-96/s_nexttowardf.c     |  3 ++
 sysdeps/ieee754/ldbl-opt/s_nexttowardfd.c   |  3 ++
 sysdeps/m68k/m680x0/fpu/s_nextafterl.c      |  3 ++
 19 files changed, 102 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index fdd9da4b98..d9c0689b6a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,42 @@
 2015-11-02  Joseph Myers  <joseph@codesourcery.com>
 
+	[BZ #6799]
+	* math/s_nextafter.c: Include <errno.h>.
+	(__nextafter): Set errno on overflow and underflow.
+	* math/s_nexttowardf.c: Include <errno.h>.
+	(__nexttowardf): Set errno on overflow and underflow.
+	* sysdeps/i386/fpu/s_nextafterl.c: Include <errno.h>.
+	(__nextafterl): Set errno on overflow and underflow.
+	* sysdeps/i386/fpu/s_nexttoward.c: Include <errno.h>.
+	(__nexttoward): Set errno on overflow and underflow.
+	* sysdeps/i386/fpu/s_nexttowardf.c: Include <errno.h>.
+	(__nexttowardf): Set errno on overflow and underflow.
+	* sysdeps/ieee754/flt-32/s_nextafterf.c: Include <errno.h>.
+	(__nextafterf): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-128/s_nextafterl.c: Include <errno.h>.
+	(__nextafterl): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-128/s_nexttoward.c: Include <errno.h>.
+	(__nexttoward): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-128/s_nexttowardf.c: Include <errno.h>.
+	(__nexttowardf): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c: Include <errno.h>.
+	(__nextafterl): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c: Include <errno.h>.
+	(__nexttoward): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c: Include <errno.h>.
+	(__nexttowardf): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-96/s_nexttoward.c: Include <errno.h>.
+	(__nexttoward): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-96/s_nexttowardf.c: Include <errno.h>.
+	(__nexttowardf): Set errno on overflow and underflow.
+	* sysdeps/ieee754/ldbl-opt/s_nexttowardfd.c: Include <errno.h>.
+	(__nldbl_nexttowardf): Set errno on overflow and underflow.
+	* sysdeps/m68k/m680x0/fpu/s_nextafterl.c: Include <errno.h>.
+	(__nextafterl): Set errno on overflow and underflow.
+	* math/libm-test.inc (nextafter_test_data): Do not allow errno
+	setting to be missing on overflow.  Add more tests.
+	(nexttoward_test_data): Likewise.
+
 	* configure.ac (libc_cv_initfini_array): Remove configure test.
 	* configure: Regenerated.
 
diff --git a/NEWS b/NEWS
index 654217c49f..1cc08a0a7c 100644
--- a/NEWS
+++ b/NEWS
@@ -9,7 +9,7 @@ Version 2.23
 
 * The following bugs are resolved with this release:
 
-  887, 2542, 2543, 2558, 2898, 4404, 6803, 10432, 14341, 14912, 15367,
+  887, 2542, 2543, 2558, 2898, 4404, 6799, 6803, 10432, 14341, 14912, 15367,
   15384, 15470, 15491, 15786, 15918, 16068, 16141, 16171, 16296, 16347,
   16399, 16415, 16422, 16517, 16519, 16520, 16521, 16620, 16734, 16973,
   16985, 17118, 17243, 17244, 17250, 17404, 17441, 17787, 17886, 17887,
diff --git a/math/libm-test.inc b/math/libm-test.inc
index ace51c977e..1267b817e7 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -9850,9 +9850,13 @@ static const struct test_ff_f_data nextafter_test_data[] =
     TEST_ff_f (nextafter, 1.1L, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
     TEST_ff_f (nextafter, qnan_value, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
 
-    /* Bug 6799: errno setting may be missing.  */
-    TEST_ff_f (nextafter, max_value, plus_infty, plus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION),
-    TEST_ff_f (nextafter, -max_value, minus_infty, minus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION),
+    TEST_ff_f (nextafter, max_value, plus_infty, plus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nextafter, -max_value, minus_infty, minus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+
+    TEST_ff_f (nextafter, min_subnorm_value, 0, 0, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nextafter, min_subnorm_value, minus_zero, 0, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nextafter, -min_subnorm_value, 0, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nextafter, -min_subnorm_value, minus_zero, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
 
 #ifdef TEST_LDOUBLE
     // XXX Enable once gcc is fixed.
@@ -9894,9 +9898,13 @@ static const struct test_ff_f_data_nexttoward nexttoward_test_data[] =
     TEST_ff_f (nexttoward, 1.1L, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
     TEST_ff_f (nexttoward, qnan_value, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
 
-    /* Bug 6799: errno setting may be missing.  */
-    TEST_ff_f (nexttoward, max_value, plus_infty, plus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION),
-    TEST_ff_f (nexttoward, -max_value, minus_infty, minus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION),
+    TEST_ff_f (nexttoward, max_value, plus_infty, plus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nexttoward, -max_value, minus_infty, minus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+
+    TEST_ff_f (nexttoward, min_subnorm_value, 0, 0, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nexttoward, min_subnorm_value, minus_zero, 0, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nexttoward, -min_subnorm_value, 0, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nexttoward, -min_subnorm_value, minus_zero, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
 
 #ifdef TEST_FLOAT
     TEST_ff_f (nexttoward, 1.0, 1.1L, 0x1.000002p0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
diff --git a/math/s_nextafter.c b/math/s_nextafter.c
index 28962e52a7..dfa5e860c4 100644
--- a/math/s_nextafter.c
+++ b/math/s_nextafter.c
@@ -25,6 +25,7 @@ static char rcsid[] = "$NetBSD: s_nextafter.c,v 1.8 1995/05/10 20:47:58 jtc Exp
 #define __nexttoward __internal___nexttoward
 #define nexttoward __internal_nexttoward
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -72,10 +73,12 @@ double __nextafter(double x, double y)
 	if(hy>=0x7ff00000) {
 	  double u = x+x;	/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00100000) {
 	    double u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	  __set_errno (ERANGE);
 	}
 	INSERT_WORDS(x,hx,lx);
 	return x;
diff --git a/math/s_nexttowardf.c b/math/s_nexttowardf.c
index 06350d47bf..30cd81b454 100644
--- a/math/s_nexttowardf.c
+++ b/math/s_nexttowardf.c
@@ -20,6 +20,7 @@
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -61,10 +62,12 @@ float __nexttowardf(float x, long double y)
 	if(hy>=0x7f800000) {
 	  float u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00800000) {
 	    float u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;
diff --git a/sysdeps/i386/fpu/s_nextafterl.c b/sysdeps/i386/fpu/s_nextafterl.c
index 66d903f801..188dc2129a 100644
--- a/sysdeps/i386/fpu/s_nextafterl.c
+++ b/sysdeps/i386/fpu/s_nextafterl.c
@@ -26,6 +26,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -109,10 +110,12 @@ long double __nextafterl(long double x, long double y)
 	if(esy==0x7fff) {
 	    long double u = x + x;	/* overflow  */
 	    math_force_eval (u);
+	    __set_errno (ERANGE);
 	}
 	if(esy==0) {
 	    long double u = x*x;		/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_LDOUBLE_WORDS(x,esx,hx,lx);
 	return x;
diff --git a/sysdeps/i386/fpu/s_nexttoward.c b/sysdeps/i386/fpu/s_nexttoward.c
index 839efe6c05..0b47044760 100644
--- a/sysdeps/i386/fpu/s_nexttoward.c
+++ b/sysdeps/i386/fpu/s_nexttoward.c
@@ -26,6 +26,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -75,10 +76,12 @@ double __nexttoward(double x, long double y)
 	if(hy>=0x7ff00000) {
 	  double u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00100000) {
 	    double u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	INSERT_WORDS(x,hx,lx);
 	return x;
diff --git a/sysdeps/i386/fpu/s_nexttowardf.c b/sysdeps/i386/fpu/s_nexttowardf.c
index 29b4f12775..e1156d1e4f 100644
--- a/sysdeps/i386/fpu/s_nexttowardf.c
+++ b/sysdeps/i386/fpu/s_nexttowardf.c
@@ -18,6 +18,7 @@
 static char rcsid[] = "$NetBSD: $";
 #endif
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -63,10 +64,12 @@ float __nexttowardf(float x, long double y)
 	if(hy>=0x7f800000) {
 	  float u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00800000) {
 	    float u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;
diff --git a/sysdeps/ieee754/flt-32/s_nextafterf.c b/sysdeps/ieee754/flt-32/s_nextafterf.c
index 22e0b3d4ed..625d54b768 100644
--- a/sysdeps/ieee754/flt-32/s_nextafterf.c
+++ b/sysdeps/ieee754/flt-32/s_nextafterf.c
@@ -17,6 +17,7 @@
 static char rcsid[] = "$NetBSD: s_nextafterf.c,v 1.4 1995/05/10 20:48:01 jtc Exp $";
 #endif
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -59,10 +60,12 @@ float __nextafterf(float x, float y)
 	if(hy>=0x7f800000) {
 	  float u = x+x;	/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00800000) {
 	    float u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-128/s_nextafterl.c b/sysdeps/ieee754/ldbl-128/s_nextafterl.c
index d5eaa1cc91..4e9a2ce520 100644
--- a/sysdeps/ieee754/ldbl-128/s_nextafterl.c
+++ b/sysdeps/ieee754/ldbl-128/s_nextafterl.c
@@ -24,6 +24,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -70,10 +71,12 @@ long double __nextafterl(long double x, long double y)
 	if(hy==0x7fff000000000000LL) {
 	    long double u = x + x;		/* overflow  */
 	    math_force_eval (u);
+	    __set_errno (ERANGE);
 	}
 	if(hy==0) {
 	    long double u = x*x;		/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_LDOUBLE_WORDS64(x,hx,lx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-128/s_nexttoward.c b/sysdeps/ieee754/ldbl-128/s_nexttoward.c
index 2ee7a1be5c..4343fe83f8 100644
--- a/sysdeps/ieee754/ldbl-128/s_nexttoward.c
+++ b/sysdeps/ieee754/ldbl-128/s_nexttoward.c
@@ -25,6 +25,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -75,10 +76,12 @@ double __nexttoward(double x, long double y)
 	if(hy>=0x7ff00000) {
 	  double u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00100000) {
 	    double u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	INSERT_WORDS(x,hx,lx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-128/s_nexttowardf.c b/sysdeps/ieee754/ldbl-128/s_nexttowardf.c
index 9c9c7e5283..8703359d4f 100644
--- a/sysdeps/ieee754/ldbl-128/s_nexttowardf.c
+++ b/sysdeps/ieee754/ldbl-128/s_nexttowardf.c
@@ -18,6 +18,7 @@
 static char rcsid[] = "$NetBSD: $";
 #endif
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -62,10 +63,12 @@ float __nexttowardf(float x, long double y)
 	if(hy>=0x7f800000) {
 	  float u = x+x;		/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00800000) {
 	    float u = x*x;		/* underflow */
 	    math_force_eval (u);	/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c b/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
index 36a5090693..515aa1ef5b 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
@@ -24,6 +24,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <float.h>
 #include <math.h>
 #include <math_private.h>
@@ -69,6 +70,7 @@ long double __nextafterl(long double x, long double y)
 	    if((hx==0xffefffffffffffffLL)&&(lx==0xfc8ffffffffffffeLL)) {
 	      u = x+x;	/* overflow, return -inf */
 	      math_force_eval (u);
+	      __set_errno (ERANGE);
 	      return y;
 	    }
 	    if (hx >= 0x7ff0000000000000LL) {
@@ -83,6 +85,7 @@ long double __nextafterl(long double x, long double y)
 		  || (hx < 0 && lx > 1)) {
 		u = u * u;
 		math_force_eval (u);		/* raise underflow flag */
+		__set_errno (ERANGE);
 	      }
 	      return x;
 	    }
@@ -108,6 +111,7 @@ long double __nextafterl(long double x, long double y)
 	    if((hx==0x7fefffffffffffffLL)&&(lx==0x7c8ffffffffffffeLL)) {
 	      u = x+x;	/* overflow, return +inf */
 	      math_force_eval (u);
+	      __set_errno (ERANGE);
 	      return y;
 	    }
 	    if ((uint64_t) hx >= 0xfff0000000000000ULL) {
@@ -122,6 +126,7 @@ long double __nextafterl(long double x, long double y)
 		  || (hx < 0 && lx >= 0)) {
 		u = u * u;
 		math_force_eval (u);		/* raise underflow flag */
+		__set_errno (ERANGE);
 	      }
 	      if (x == 0.0L)	/* handle negative LDBL_TRUE_MIN case */
 		x = -0.0L;
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c b/sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c
index 8c6119825e..d8f4fc6523 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c
@@ -25,6 +25,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <math_ldbl_opt.h>
@@ -76,10 +77,12 @@ double __nexttoward(double x, long double y)
 	if(hy>=0x7ff00000) {
 	  double u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00100000) {
 	    double u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	INSERT_WORDS(x,hx,lx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c b/sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c
index 4000a93e69..7c5d1cc112 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c
@@ -18,6 +18,7 @@
 static char rcsid[] = "$NetBSD: $";
 #endif
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <math_ldbl_opt.h>
@@ -65,10 +66,12 @@ float __nexttowardf(float x, long double y)
 	if(hy>=0x7f800000) {
 	  float u = x+x;		/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00800000) {		/* underflow */
 	    float u = x*x;
 	    math_force_eval (u);	/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-96/s_nexttoward.c b/sysdeps/ieee754/ldbl-96/s_nexttoward.c
index 7908f9c0ff..3d0382eac9 100644
--- a/sysdeps/ieee754/ldbl-96/s_nexttoward.c
+++ b/sysdeps/ieee754/ldbl-96/s_nexttoward.c
@@ -25,6 +25,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -72,10 +73,12 @@ double __nexttoward(double x, long double y)
 	if(hy>=0x7ff00000) {
 	  double u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00100000) {
 	    double u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	INSERT_WORDS(x,hx,lx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-96/s_nexttowardf.c b/sysdeps/ieee754/ldbl-96/s_nexttowardf.c
index 53c527d9ac..ae7538942f 100644
--- a/sysdeps/ieee754/ldbl-96/s_nexttowardf.c
+++ b/sysdeps/ieee754/ldbl-96/s_nexttowardf.c
@@ -17,6 +17,7 @@
 static char rcsid[] = "$NetBSD: $";
 #endif
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -60,10 +61,12 @@ float __nexttowardf(float x, long double y)
 	if(hy>=0x7f800000) {
 	  float u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00800000) {
 	    float u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-opt/s_nexttowardfd.c b/sysdeps/ieee754/ldbl-opt/s_nexttowardfd.c
index dbcf840f2c..07e9375b78 100644
--- a/sysdeps/ieee754/ldbl-opt/s_nexttowardfd.c
+++ b/sysdeps/ieee754/ldbl-opt/s_nexttowardfd.c
@@ -20,6 +20,7 @@
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <math_ldbl_opt.h>
@@ -64,10 +65,12 @@ float __nldbl_nexttowardf(float x, double y)
 	if(hy>=0x7f800000) {
 	  float u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00800000) {
 	    float u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;
diff --git a/sysdeps/m68k/m680x0/fpu/s_nextafterl.c b/sysdeps/m68k/m680x0/fpu/s_nextafterl.c
index ad77ca4f67..c46c0e76ec 100644
--- a/sysdeps/m68k/m680x0/fpu/s_nextafterl.c
+++ b/sysdeps/m68k/m680x0/fpu/s_nextafterl.c
@@ -26,6 +26,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -92,10 +93,12 @@ long double __nextafterl(long double x, long double y)
 	if(esy==0x7fff) {
 	    long double u = x + x;	/* overflow  */
 	    math_force_eval (u);
+	    __set_errno (ERANGE);
 	}
 	if(esy==0 && (hx & 0x80000000) == 0) { /* underflow */
 	    y = x*x;
 	    math_force_eval (y);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_LDOUBLE_WORDS(x,esx,hx,lx);
 	return x;