Is command 'mktemp' portable?

[Pavel S. Shirshov]

Hello,

I'm having patches for fix problem with security of mc.
It's good candidate for commiting into CVS tree now.
But, this patches was used mktemp, e.g.

         MAN=%{Enter name of man:}
-        TMPFILE=/tmp/mcview.$MAN.$$
+        TMPFILE=`mktemp ${MC_TMPDIR:-/tmp}/mcview.$MAN.$$` || exit 1
         man -Pcat $MAN >$TMPFILE
         mcview $TMPFILE
         rm -f $TMPFILE

Is command 'mktemp' portable?

P.S.: Sorry for bad English.

-- 
Best regards,
 Pavel                          mailto:pavelsh at mail.ru