[tetex 3.0] Swapping between dvi and pdf

I used ensure I got the right output by having constructs at the top
of the source files like this:

\newif\ifpdf
\ifx\pdfoutput\undefined
    \pdffalse       % we are not running PDFLaTeX
\else
    \pdfoutput=1    % we are running PDFLaTeX
    \pdftrue
\fi

\ifpdf
 ... do some pdf things
\fi

\ifpdf
  \usepackage[pdftex]{color}
\else
  \usepackage{color}
\fi

and so on.

latex file      didn't define "pdfoutput" so it miised the PDF stuff out
                  and crated a DVI

pdflatex file   did define "pdfoutput" so it included PDF specific stuff
                 and created a PDF

teTex's pdflatex/latex always seems ot define pdfoutput even when 
I try   -output-format=dvi

Have I missed something ?

Could I just have installed it incorrectly ?

Reading the obvious posting at the list archive, I get the idea I
might not have to do the jumping through \ifdef\pdfoutput anyway
but so far, the penny (pfennig ?) hasn't dropped for me.

-- 
Regards,

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*  Kevin M. Buckley              e-mail: [email protected]   *
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*  Systems Administrator                                             *
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*  My PC runs Linux/GNU, you still computing the Bill Gate$' way ?   *
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