This function is missing on some platforms:
mingw, Interix 3.5, BeOS.
@item
+The declaration of this function lacks @code{const} in the second argument
+on some platforms:
+OSF/1 5.1.
+@item
On some platforms, this function mis-handles trailing slash:
FreeBSD 7.2, Solaris 9.
@item
@code{utime} worked fine.
glibc 2.2.5.
@end itemize
+
+Extension: Gnulib provides a module @samp{utimens} that works around these
+problems and allows to set the time with nanosecond resolution (as far as
+supported by the file system).