mktemp(1) in /tmp or $PWD?

[Garrett Cooper]

Hi Hackers,
    Really basic question (because I'm relatively new to the Unix
scene -- only been using it for the last 10 years, so I don't know if
this was done for backwards compatibility with SysV) -- is mktemp(1)
without -t supposed to default to $PWD instead of /tmp if a template
is specified, e.g.

[root at left4dead /usr/home/garrcoop]# mktemp fooXXXXXX
foovE3FLt
[root at left4dead /usr/home/garrcoop]# ls foovE3FLt
foovE3FLt

    I ask because GNU coreutils' copy of mktemp (I know... I know...)
defaults to /tmp if $TMPDIR isn't specified.
Thanks!
-Garrett