utimes(2),utime(3): Add deprecation in favour of utimensat(2) and futimens(2).

Setting time by seconds or microseconds may cause unexpected effects
especially if sysctl vfs.timestamp_precision=3 (not default).

Calling the obsolete functions with NULL timestamps is acceptable.

lib/libc/gen/utime.3

@@ -28,7 +28,7 @@
 .\"     @(#)utime.3	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd June 4, 1993
+.Dd June 9, 2016
 .Dt UTIME 3
 .Os
 .Sh NAME
@@ -43,7 +43,8 @@
 .Sh DESCRIPTION
 .Bf -symbolic
 This interface is obsoleted by
-.Xr utimes 2 .
+.Xr utimensat 2
+because it is not accurate to fractions of a second.
 .Ef
 .Pp
 The
@@ -79,6 +80,7 @@ for any of the errors specified for the library function
 .Xr utimes 2 .
 .Sh SEE ALSO
 .Xr stat 2 ,
+.Xr utimensat 2 ,
 .Xr utimes 2
 .Sh STANDARDS
 The

lib/libc/sys/utimes.2

@@ -30,7 +30,7 @@
 .\"     @(#)utimes.2	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd July 3, 2014
+.Dd June 9, 2016
 .Dt UTIMES 2
 .Os
 .Sh NAME
@@ -52,6 +52,14 @@
 .Ft int
 .Fn futimesat "int fd" "const char *path" "const struct timeval times[2]"
 .Sh DESCRIPTION
+.Bf -symbolic
+These interfaces are obsoleted by
+.Xr futimens 2
+and
+.Xr utimensat 2
+because they are not accurate to nanoseconds.
+.Ef
+.Pp
 The access and modification times of the file named by
 .Fa path
 or referenced by
@@ -223,6 +231,7 @@ nor a file descriptor associated with a directory.
 .Sh SEE ALSO
 .Xr chflags 2 ,
 .Xr stat 2 ,
+.Xr utimensat 2 ,
 .Xr utime 3
 .Sh STANDARDS
 The
@@ -231,7 +240,11 @@ function is expected to conform to
 .St -xpg4.2 .
 The
 .Fn futimesat
-system call follows The Open Group Extended API Set 2 specification.
+system call follows The Open Group Extended API Set 2 specification
+but was replaced by
+.Fn utimensat
+in
+.St -p1003.1-2008 .
 .Sh HISTORY
 The
 .Fn utimes