% \iffalse meta-comment
%
% Copyright (C) 2001, 2005, 2006 by
%    Heiko Oberdiek <oberdiek@uni-freiburg.de>
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either
% version 1.3 of this license or (at your option) any later
% version. The latest version of this license is in
%    http://www.latex-project.org/lppl.txt
% and version 1.3 or later is part of all distributions of
% LaTeX version 2005/12/01 or later.
%
% This work has the LPPL maintenance status "maintained".
%
% This Current Maintainer of this work is Heiko Oberdiek.
%
% This work consists of the main source file ifpdf.dtx
% and the derived files
%    ifpdf.sty, ifpdf.pdf, ifpdf.ins, ifpdf.drv.
%
% Distribution:
%    CTAN:macros/latex/contrib/oberdiek/ifpdf.dtx
%    CTAN:macros/latex/contrib/oberdiek/ifpdf.pdf
%
% Unpacking:
%    (a) If ifpdf.ins is present:
%           tex ifpdf.ins
%    (b) Without ifpdf.ins:
%           tex ifpdf.dtx
%    (c) If you insist on using LaTeX
%           latex \let\install=y\input{ifpdf.dtx}
%        (quote the arguments according to the demands of your shell)
%
% Documentation:
%    (a) If ifpdf.drv is present:
%           latex ifpdf.drv
%    (b) Without ifpdf.drv:
%           latex ifpdf.dtx; ...
%    The class ltxdoc loads the configuration file ltxdoc.cfg
%    if available. Here you can specify further options, e.g.
%    use A4 as paper format:
%       \PassOptionsToClass{a4paper}{article}
%
%    Programm calls to get the documentation (example):
%       pdflatex ifpdf.dtx
%       makeindex -s gind.ist ifpdf.idx
%       pdflatex ifpdf.dtx
%       makeindex -s gind.ist ifpdf.idx
%       pdflatex ifpdf.dtx
%
% Installation:
%    TDS:tex/generic/oberdiek/ifpdf.sty
%    TDS:doc/latex/oberdiek/ifpdf.pdf
%    TDS:source/latex/oberdiek/ifpdf.dtx
%
%<*ignore>
\begingroup
  \def\x{LaTeX2e}
\expandafter\endgroup
\ifcase 0\ifx\install y1\fi\expandafter
         \ifx\csname processbatchFile\endcsname\relax\else1\fi
         \ifx\fmtname\x\else 1\fi\relax
\else\csname fi\endcsname
%</ignore>
%<*install>
\input docstrip.tex
\Msg{************************************************************************}
\Msg{* Installation}
\Msg{* Package: ifpdf 2006/02/20 v1.4 Provides the ifpdf switch (HO)}
\Msg{************************************************************************}

\keepsilent
\askforoverwritefalse

\preamble

This is a generated file.

Copyright (C) 2001, 2005, 2006 by
   Heiko Oberdiek <oberdiek@uni-freiburg.de>

This work may be distributed and/or modified under the
conditions of the LaTeX Project Public License, either
version 1.3 of this license or (at your option) any later
version. The latest version of this license is in
   http://www.latex-project.org/lppl.txt
and version 1.3 or later is part of all distributions of
LaTeX version 2005/12/01 or later.

This work has the LPPL maintenance status "maintained".

This Current Maintainer of this work is Heiko Oberdiek.

This work consists of the main source file ifpdf.dtx
and the derived files
   ifpdf.sty, ifpdf.pdf, ifpdf.ins, ifpdf.drv.

\endpreamble

\generate{%
  \file{ifpdf.ins}{\from{ifpdf.dtx}{install}}%
  \file{ifpdf.drv}{\from{ifpdf.dtx}{driver}}%
  \usedir{tex/generic/oberdiek}%
  \file{ifpdf.sty}{\from{ifpdf.dtx}{package}}%
}

\obeyspaces
\Msg{************************************************************************}
\Msg{*}
\Msg{* To finish the installation you have to move the following}
\Msg{* file into a directory searched by TeX:}
\Msg{*}
\Msg{*     ifpdf.sty}
\Msg{*}
\Msg{* To produce the documentation run the file `ifpdf.drv'}
\Msg{* through LaTeX.}
\Msg{*}
\Msg{* Happy TeXing!}
\Msg{*}
\Msg{************************************************************************}

\endbatchfile
%</install>
%<*ignore>
\fi
%</ignore>
%<*driver>
\NeedsTeXFormat{LaTeX2e}
\ProvidesFile{ifpdf.drv}%
  [2006/02/20 v1.4 Provides the ifpdf switch (HO)]
\documentclass{ltxdoc}
\usepackage{holtxdoc}
\begin{document}
  \DocInput{ifpdf.dtx}
\end{document}
%</driver>
% \fi
%
% \CheckSum{156}
%
% \CharacterTable
%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
%   Lower-case    \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
%   Digits        \0\1\2\3\4\5\6\7\8\9
%   Exclamation   \!     Double quote  \"     Hash (number) \#
%   Dollar        \$     Percent       \%     Ampersand     \&
%   Acute accent  \'     Left paren    \(     Right paren   \)
%   Asterisk      \*     Plus          \+     Comma         \,
%   Minus         \-     Point         \.     Solidus       \/
%   Colon         \:     Semicolon     \;     Less than     \<
%   Equals        \=     Greater than  \>     Question mark \?
%   Commercial at \@     Left bracket  \[     Backslash     \\
%   Right bracket \]     Circumflex    \^     Underscore    \_
%   Grave accent  \`     Left brace    \{     Vertical bar  \|
%   Right brace   \}     Tilde         \~}
%
% \GetFileInfo{ifpdf.drv}
%
% \title{The \xpackage{ifpdf} package}
% \date{2006/02/20 v1.4}
% \author{Heiko Oberdiek\\\xemail{oberdiek@uni-freiburg.de}}
%
% \maketitle
%
% \begin{abstract}
% This package looks for pdfTeX in pdf mode and
% implements and sets the switch \cs{ifpdf}.
% The detection is based on \cs{pdfoutput} and
% the package will not change this value.
% It works with plain or LaTeX formats.
% \end{abstract}
%
% \tableofcontents
%
% \hypersetup{bookmarksopenlevel=2}
% \section{Documentation}
%
% \subsection{Introduction}
%
% It is commonly known that H\`an Th\^e Th\`anh's \pdfTeX\ generates
% PDF output directly and many people uses \pdfTeX\ for this purpose.
% However the DVI output was never thrown away. In contrary, he
% new features for typesetting that works in both PDF and DVI mode.
%
% In the meantime many \TeX\ distributions replace the traditional
% \TeX\ binary with \pdfTeX. Then, for example, called as |latex|
% \pdfTeX\ works in DVI mode with the \LaTeX\ format preloaded,
% called as |pdflatex| \pdfTeX\ starts in PDF mode.
%
% Often packages or users want to know, whether the current document
% is typset by \pdfTeX\ in PDF mode, because the different modes
% have different capabilities (color setting, graphics inclusion,
% \dots). For this purpose \pdfTeX's
% \cs{pdfoutput} can be asked.
%
% As regulary reader of \TeX\ newsgroups and mailing lists I could
% observe many problems with this task. Common errors are:
% \begin{itemize}
% \item
%   \pdfTeX\ has \emph{two} modes. Using \pdfTeX\ does not mean
%   that the user always want to have PDF mode. For example, the
%   PostScript support is better in DVI mode in conjunction with a
%   PostScript aware DVI driver (e.g. dvips). Also the additional
%   typesetting features are mode independent and also available
%   in DVI mode.
% \item
%   \LaTeX's \cs{@ifundefined} inherited the side effect from
%   \cs{csname}. Unknown commands are defined with the meaning
%   of \cs{relax}. If it is checked, whether \cs{pdfoutput} is
%   defined, then this should not be forgotten.
% \item
%   Having \cs{pdfoutput} does not automatically mean PDF mode.
%   Also the value of \cs{pdfoutput} must be asked.
% \item
%   \cs{pdfoutput} must not be destroyed in some way. Later
%   code and packages are fooled then and will perhaps make
%   wrong decisions. For example they may drop support for
%   PDF mode, because they do not know that \pdfTeX\ is
%   running at all.
% \end{itemize}
%
% Robin Fairbairns provides an entry for this topic in his
% excellent FAQ (\url{http://www.tex.ac.uk/faq}):
% \href{http://www.tex.ac.uk/cgi-bin/texfaq2html?label=ifpdf}^^A
% {Am I using PDFTeX?}
%
% \subsection{Usage}
%
% The package \xpackage{ifpdf} can be used with both \plainTeX\
% and \LaTeX:
% \begin{description}
% \item[\plainTeX:] |\input ifpdf.sty|
% \item[\LaTeXe:]   |\usepackage{ifpdf}|\\
% \end{description}
%
% \DescribeMacro{\ifpdf}
% The package provides the switch \cs{ifpdf}:
% \begin{quote}
%   |\ifpdf|\\
%   \hspace{1.5em}\dots\ do things, if \pdfTeX\ is running in pdf mode \dots\\
%   |\else|\\
%   \hspace{1.5em}\dots\ other \TeX\ or \pdfTeX\ in dvi mode \dots\\
%   |\fi|
% \end{quote}
% Users of the package \xpackage{ifthen} can use the switch as boolean:
% \begin{quote}
%   |\boolean{ifpdf}|
% \end{quote}
% The package can also be used to set global
% documentclass options:
% \begin{quote}
%   |\RequirePackage{ifpdf}|\\
%   |\ifpdf|\\
%   \hspace{1.5em}|\documentclass[pdftex,|\dots|]{|\dots|}|\\
%   |\else|\\
%   \hspace{1.5em}|\documentclass[|\dots|]{|\dots|}|\\
%   |\fi|
% \end{quote}
%
% \subsection{Specification}
%
% The package have the following properties:
% \begin{itemize}
% \item It asks the setting of \cs{pdfoutput} for detecting
%   \pdfTeX\ in PDF mode.
% \item It never changes \cs{pdfoutput}.
% \item It can be used with many formats including
%   \plainTeX\ and \LaTeX.
% \end{itemize}
% The mode detection implements the following algorithm:
% \begin{quote}
% \def\={${:}{=}$}
% \def\>{\null\qquad\ignorespaces}
% \def\comment#1{^^A
%   \textrm{\itshape\% #1}^^A
% }
% \sffamily
% if undefined(\cs{pdfoutput})\\
% \> \cs{ifpdf} \= \cs{iffalse} \comment{\pdfTeX is not running}\\
% else\\
% \> if \cs{pdfoutput} $\leq$ 0\\
% \>\> \cs{ifpdf} \= \cs{iffalse} \comment{\pdfTeX\ in DVI mode}\\
% \> else\\
% \>\> \cs{ifpdf} \= \cs{iftrue} \comment{\pdfTeX\ in PDF mode}\\
% \> fi\\
% fi
% \end{quote}
% The function \textsf{undefined} checks both cases, undefined command
% and \cs{relax}.
%
% \subsection{Future}
%
% Currently the package can be fooled, by redefining/undefining
% \cs{pdfoutput}. Therefore the package will use the \cs{primitive}
% feature that is discussed currently on the \pdfTeX\ developer
% list (2006), if it hits a stable release. Of course the package
% will then remain usable with older \pdfTeX\ versions as usual.
%
% \hypersetup{bookmarksopenlevel=1}
%
% \StopEventually{
% }
%
% \section{Implementation}
%
%    \begin{macrocode}
%<*package>
%    \end{macrocode}
%
% \subsection{Reload check and package identification}
%    Reload check, especially if the package is not used with \LaTeX.
%    \begin{macrocode}
\begingroup
  \expandafter\let\expandafter\x\csname ver@ifpdf.sty\endcsname
  \ifcase 0%
    \ifx\x\relax % plain
    \else
      \ifx\x\empty % LaTeX
      \else
        1%
      \fi
    \fi
  \else
    \expandafter\ifx\csname PackageInfo\endcsname\relax
      \def\x#1#2{%
        \immediate\write-1{Package #1 Info: #2.}%
      }%
    \else
      \def\x#1#2{\PackageInfo{#1}{#2, stopped}}%
    \fi
    \x{ifpdf}{The package is already loaded}%
    \endgroup
    \expandafter\endinput
  \fi
\endgroup
%    \end{macrocode}
%    Package identification:
%    \begin{macrocode}
\begingroup
  \expandafter\ifx\csname ProvidesPackage\endcsname\relax
    \def\x#1#2#3[#4]{\endgroup
      \immediate\write-1{Package: #3 #4}%
      \xdef#1{#4}%
    }%
  \else
    \def\x#1#2[#3]{\endgroup
      #2[{#3}]%
      \ifx#1\relax
        \xdef#1{#3}%
      \fi
    }%
  \fi
\expandafter\x\csname ver@ifpdf.sty\endcsname
\ProvidesPackage{ifpdf}%
  [2006/02/20 v1.4 Provides the ifpdf switch (HO)]
%    \end{macrocode}
%
% \subsection{Check for previously defined \cs{ifpdf}}
%
%    \begin{macrocode}
\begingroup
  \expandafter\ifx\csname ifpdf\endcsname\relax
  \else
    \edef\i/{\expandafter\string\csname ifpdf\endcsname}%
    \expandafter\ifx\csname PackageError\endcsname\relax
      \def\x#1#2{%
        \edef\z{#2}%
        \expandafter\errhelp\expandafter{\z}%
        \errmessage{Package ifpdf Error: #1}%
      }%
      \def\y{^^J}%
      \newlinechar=10
    \else
      \def\x#1#2{%
        \PackageError{ifpdf}{#1}{#2}%
      }%
      \def\y{\MessageBreak}%
    \fi
    \x{Name clash, \i/ is already defined}{%
      Incompatible versions of \i/ can cause problems,\y
      therefore package loading is aborted.%
    }%
    \endgroup
    \expandafter\endinput
  \fi
\endgroup
%    \end{macrocode}
%
% \subsection{\cs{ifpdf}}
%
%    \begin{macro}{\ifpdf}
%    Create and set the switch. \cs{newif} initializes the
%    switch with \cs{iffalse}.
%    \begin{macrocode}
\newif\ifpdf
%    \end{macrocode}
%    Test \cs{pdfoutput}. Is it  defined and different from
%    \cs{relax}? Someone could have used \LaTeX\ internal
%    \cs{@ifundefined}, or something else involving.
%    Notice, \cs{csname} is executed inside a group for the test
%    to cancel the side effect of \cs{csname}.
%    \begin{macrocode}
\begingroup\expandafter\expandafter\expandafter\endgroup
\expandafter\ifx\csname pdfoutput\endcsname\relax
\else
  \ifnum\pdfoutput<1 %
%    \end{macrocode}
%    \cs{pdfoutput}|=0| or negative, so not generating pdf.
%    \begin{macrocode}
  \else
    \pdftrue
  \fi
\fi
%    \end{macrocode}
%    \end{macro}
%
% \subsection{Protocol entry}
%
%     Log comment:
%    \begin{macrocode}
\begingroup
  \expandafter\ifx\csname PackageInfo\endcsname\relax
    \def\x#1#2{%
      \immediate\write-1{Package #1 Info: #2.}%
    }%
  \else
    \let\x\PackageInfo
    \expandafter\let\csname on@line\endcsname\empty
  \fi
  \x{ifpdf}{pdfTeX in pdf mode \ifpdf\else not \fi detected}%
\endgroup
%    \end{macrocode}
%    \begin{macrocode}
%</package>
%    \end{macrocode}
% \section{Installation}
%
% \paragraph{CTAN.} This package is available on
% CTAN\footnote{\url{ftp://ftp.ctan.org/tex-archive/}}:
% \begin{description}
% \item[\CTAN{macros/latex/contrib/oberdiek/ifpdf.dtx}] The source file.
% \item[\CTAN{macros/latex/contrib/oberdiek/ifpdf.pdf}] Documentation.
% \end{description}
%
% \paragraph{Unpacking.} The \xfile{.dtx} file is a self-extracting
% \docstrip\ archive. The files are extracted by running the
% \xfile{.dtx} through \plainTeX:
% \begin{quote}
%   \verb|tex ifpdf.dtx|
% \end{quote}
%
% \paragraph{TDS.} Now the different files must be moved into
% the different directories in your installation TDS tree
% (also known as \xfile{texmf} tree):
% \begin{quote}
% \sbox0{^^A
% \begin{tabular}{@{}>{\ttfamily}l@{$\quad\rightarrow\quad$}>{\ttfamily}l@{}}
%   ifpdf.sty & tex/generic/oberdiek/ifpdf.sty\\
%   ifpdf.pdf & doc/latex/oberdiek/ifpdf.pdf\\
%   ifpdf.dtx & source/latex/oberdiek/ifpdf.dtx\\
% \end{tabular}^^A
% }%
% \ifdim\wd0>\linewidth
%   \mbox{}\nobreak\hskip0pt minus\leftmargin
%   \usebox0
%   \nobreak\hskip0pt minus\rightmargin
% \else
%   \usebox0
% \fi
% \end{quote}
% If you have a \xfile{docstrip.cfg} that configures and enables \docstrip's
% TDS installing feature, then some files can already be in the right
% place, see the documentation of \docstrip.
%
% \paragraph{Refresh file databases.} If your \TeX~distribution
% (\teTeX, \mikTeX, \dots) rely on file databases, you must refresh
% these. For example, \teTeX\ users run \verb|texhash| or
% \verb|mktexlsr|.
%
% \subsection{Some details for the interested}
%
% \paragraph{Attached source.}
%
% The PDF documentation on CTAN also includes the
% \xfile{.dtx} source file. It can be extracted by
% AcrobatReader 6 or higher. Another option is \textsf{pdftk},
% e.g. unpack the file into the current directory:
% \begin{quote}
%   \verb|pdftk ifpdf.pdf unpack_files output .|
% \end{quote}
%
% \paragraph{Unpacking with \LaTeX.}
% The \xfile{.dtx} chooses its action depending on the format:
% \begin{description}
% \item[\plainTeX:] Run \docstrip\ and extract the files.
% \item[\LaTeX:] Generate the documentation.
% \end{description}
% If you insist on using \LaTeX\ for \docstrip\ (really,
% \docstrip\ does not need \LaTeX), then inform the autodetect routine
% about your intention:
% \begin{quote}
%   \verb|latex \let\install=y\input{ifpdf.dtx}|
% \end{quote}
% Do not forget to quote the argument according to the demands
% of your shell.
%
% \paragraph{Generating the documentation.}
% You can use both the \xfile{.dtx} or the \xfile{.drv} to generate
% the documentation. The process can be configured by the
% configuration file \xfile{ltxdoc.cfg}. For instance, put this
% line into this file, if you want to have A4 as paper format:
% \begin{quote}
%   \verb|\PassOptionsToClass{a4paper}{article}|
% \end{quote}
% An example follows how to generate the
% documentation with pdf\LaTeX:
% \begin{quote}
%\begin{verbatim}
%pdflatex ifpdf.dtx
%makeindex -s gind.ist ifpdf.idx
%pdflatex ifpdf.dtx
%makeindex -s gind.ist ifpdf.idx
%pdflatex ifpdf.dtx
%\end{verbatim}
% \end{quote}
%
% \begin{History}
%   \begin{Version}{2001/06/14 v1.0}
%   \item
%     First public version,
%   \end{Version}
%   \begin{Version}{2001/07/14 v1.1}
%   \item
%     Documentation addition: global options
%   \end{Version}
%   \begin{Version}{2001/09/26 v1.2}
%   \item
%     Documentation typo corrected.
%   \item
%     Version number corrected.
%   \item
%     Line number in log entry removed.
%   \end{Version}
%   \begin{Version}{2005/07/22 v1.3}
%   \item
%     Some source code comments from Robin Fairbairns added.
%   \item
%     Bug fix for negative values of \cs{pdfoutput}
%     (Oleg Katsitadze)
%   \item
%     LPPL 1.3
%   \item
%     Installation section with locations added.
%   \end{Version}
%   \begin{Version}{2006/02/20 v1.4}
%   \item
%     DTX framework.
%   \item
%     More robust check in case of undefined \cs{pdfoutput}.
%   \item
%     Extended documentation.
%   \end{Version}
% \end{History}
%
% \PrintIndex
%
% \Finale
\endinput
