diff --git a/common/lib/libc/stdlib/_strtoi.h b/common/lib/libc/stdlib/_strtoi.h
index e6b0ce778b60..b838608f6b52 100644
--- a/common/lib/libc/stdlib/_strtoi.h
+++ b/common/lib/libc/stdlib/_strtoi.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: _strtoi.h,v 1.2 2015/01/18 17:55:22 christos Exp $	*/
+/*	$NetBSD: _strtoi.h,v 1.3 2024/01/20 16:13:39 christos Exp $	*/
 
 /*-
  * Copyright (c) 1990, 1993
@@ -100,26 +100,26 @@ INT_FUNCNAME(_int_, _FUNCNAME, _l)(const char * __restrict nptr,
 	errno = serrno;
 #endif
 
-	if (*rstatus == 0) {
-		/* No digits were found */
-		if (nptr == *endptr)
-			*rstatus = ECANCELED;
-		/* There are further characters after number */
-		else if (**endptr != '\0')
-			*rstatus = ENOTSUP;
-	}
+	/* No digits were found */
+	if (*rstatus == 0 && nptr == *endptr)
+		*rstatus = ECANCELED;
 
 	if (im < lo) {
 		if (*rstatus == 0)
 			*rstatus = ERANGE;
 		return lo;
 	}
+
 	if (im > hi) {
 		if (*rstatus == 0)
 			*rstatus = ERANGE;
 		return hi;
 	}
 
+	/* There are further characters after number */
+	if (*rstatus == 0 && **endptr != '\0')
+		*rstatus = ENOTSUP;
+
 	return im;
 }
 
diff --git a/lib/libc/stdlib/strtoi.3 b/lib/libc/stdlib/strtoi.3
index c0d10c0c4ff1..6799aaf6a15a 100644
--- a/lib/libc/stdlib/strtoi.3
+++ b/lib/libc/stdlib/strtoi.3
@@ -1,4 +1,4 @@
-.\"	$NetBSD: strtoi.3,v 1.7 2017/07/03 21:32:50 wiz Exp $
+.\"	$NetBSD: strtoi.3,v 1.8 2024/01/20 16:13:39 christos Exp $
 .\"
 .\" Copyright (c) 1990, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -36,12 +36,12 @@
 .\" Created by Kamil Rytarowski, based on ID:
 .\" NetBSD: strtol.3,v 1.31 2015/03/11 09:57:35 wiz Exp
 .\"
-.Dd November 13, 2015
+.Dd January 20, 2024
 .Dt STRTOI 3
 .Os
 .Sh NAME
 .Nm strtoi
-.Nd convert string value to an intmax_t integer
+.Nd convert a string value to an intmax_t integer
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
@@ -58,8 +58,7 @@
 .Sh DESCRIPTION
 The
 .Fn strtoi
-function
-converts the string in
+function converts the string in
 .Fa nptr
 to an
 .Ft intmax_t
@@ -117,10 +116,11 @@ is taken as 10 (decimal) unless the next character is
 .Ql 0 ,
 in which case it is taken as 8 (octal).
 .Pp
-The remainder of the string is converted to a
+The remainder of the string is converted to an
 .Em intmax_t
 value in the obvious manner,
-stopping at the first character which is not a valid digit
+stopping at the end of the string
+or at the first character which is not a valid digit
 in the given base.
 (In bases above 10, the letter
 .Ql A
@@ -201,6 +201,12 @@ or the range given was invalid, i.e.
 >
 .Fa hi .
 .El
+.Pp
+The range check is important than the unconverted characters check,
+and it is performed first.
+If a program needs to know if there were unconverted characters when an
+out of range number has been provided, it needs to supply and test
+.Fa endptr.
 .Sh SEE ALSO
 .Xr atof 3 ,
 .Xr atoi 3 ,
diff --git a/lib/libc/stdlib/strtonum.c b/lib/libc/stdlib/strtonum.c
index 35ae6d2bda62..fb92a0361161 100644
--- a/lib/libc/stdlib/strtonum.c
+++ b/lib/libc/stdlib/strtonum.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: strtonum.c,v 1.6 2018/12/06 06:29:56 kamil Exp $	*/
+/*	$NetBSD: strtonum.c,v 1.7 2024/01/20 16:13:39 christos Exp $	*/
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -29,7 +29,7 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: strtonum.c,v 1.6 2018/12/06 06:29:56 kamil Exp $");
+__RCSID("$NetBSD: strtonum.c,v 1.7 2024/01/20 16:13:39 christos Exp $");
 
 #include "namespace.h"
 
@@ -46,26 +46,33 @@ strtonum(const char *nptr, long long minval, long long maxval,
 	int e;
 	long long rv;
 	const char *resp;
+	char *eptr;
 
 	if (errstr == NULL)
 		errstr = &resp;
 
-	if (minval > maxval) {
-		*errstr = "invalid";
-		return 0;
-	}
+	if (minval > maxval)
+		goto out;
 
-	rv = (long long)strtoi(nptr, NULL, 10, minval, maxval, &e);
+	rv = (long long)strtoi(nptr, &eptr, 10, minval, maxval, &e);
 
-	if (e == 0) {
+	switch (e) {
+	case 0:
 		*errstr = NULL;
 		return rv;
+	case ECANCELED:
+	case ENOTSUP:
+		goto out;
+	case ERANGE:
+		if (*eptr)
+			goto out;
+		*errstr = rv == maxval ? "too large" : "too small";
+		return 0;
+	default:
+		abort();
 	}
 
-	if (e == ERANGE)
-		*errstr = (rv == maxval ? "too large" : "too small");
-	else
-		*errstr = "invalid";
-
+out:
+	*errstr = "invalid";
 	return 0;
 }
diff --git a/lib/libc/stdlib/strtou.3 b/lib/libc/stdlib/strtou.3
index 98ceb8ce5cbf..eb9b74927f4f 100644
--- a/lib/libc/stdlib/strtou.3
+++ b/lib/libc/stdlib/strtou.3
@@ -1,4 +1,4 @@
-.\"	$NetBSD: strtou.3,v 1.7 2017/07/03 21:32:50 wiz Exp $
+.\"	$NetBSD: strtou.3,v 1.8 2024/01/20 16:13:39 christos Exp $
 .\"
 .\" Copyright (c) 1990, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -36,12 +36,12 @@
 .\" Created by Kamil Rytarowski, based on ID:
 .\" NetBSD: strtoul.3,v 1.29 2015/03/10 13:00:58 christos Exp
 .\"
-.Dd November 13, 2015
+.Dd January 20, 2024
 .Dt STRTOU 3
 .Os
 .Sh NAME
 .Nm strtou
-.Nd convert a string to an uintmax_t integer
+.Nd convert a string value to an uintmax_t integer
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
@@ -120,7 +120,7 @@ The remainder of the string is converted to an
 .Em uintmax_t
 value in the obvious manner,
 stopping at the end of the string
-or at the first character that does not produce a valid digit
+or at the first character which is not a valid digit
 in the given base.
 (In bases above 10, the letter
 .Ql A
@@ -195,12 +195,18 @@ In this case,
 .Fa endptr
 points to the first unconverted character.
 .It Bq Er ERANGE
-The given string was out of range; the value converted has been clamped; or
-the range given was invalid, i.e.
+The given string was out of range; the value converted has been clamped;
+or the range given was invalid, i.e.
 .Fa lo
 >
 .Fa hi .
 .El
+.Pp
+The range check is important than the unconverted characters check,
+and it is performed first.
+If a program needs to know if there were unconverted characters when an
+out of range number has been provided, it needs to supply and test
+.Fa endptr.
 .Sh SEE ALSO
 .Xr atof 3 ,
 .Xr atoi 3 ,